Fermi and dark matter

[Michael Mozina]

I'm curious why astronomers as a group are allowed to simply point at the sky and make stuff up in an ad hoc manner? What empirical evidence demonstrates that "dark matter" releases gamma rays or positrons? Without such empirical validation, what it the world are they doing pointing at the sky with the Fermi telescope and claiming "dark matter did it" ?

[Ziggurat]

I'm curious why astronomers as a group are allowed to simply point at the sky and make stuff up in an ad hoc manner? What empirical evidence demonstrates that "dark matter" releases gamma rays or positrons? Without such empirical validation, what it the world are they doing pointing at the sky with the Fermi telescope and claiming "dark matter did it" ?

Oh, the irony of you accusing others of making stuff up.

And you clearly don't understand what the Fermi telescope is doing. Nobody is claiming that dark matter is emitting gamma rays or positrons.

[edd]

Dark matter is something currently unexplained. That does not mean there are no tentative explanations. Some of these tentative explanations expect dark matter to annihilate with itself, but for the chance of this to be very low. However, we expect dark matter densities to peak strongly at the centre of galaxies and so there is a prediction that dark matter will annihilate at an appreciable rate at galactic cores.

One of the things Fermi is doing is looking for this. Having predictions and testing them is a good thing.

A negative result does not rule out dark matter but it constrains what it might be.

The idea is to test hypotheses. Is this so unreasonable?

[Michael Mozina]

Oh, the irony of you accusing others of making stuff up.

http://www.newscientist.com/article/dn15126-where-will-new-fermi-telescope-find-dark-matter.html

What the hell are you talking about?

And you clearly don't understand what the Fermi telescope is doing. Nobody is claiming that dark matter is emitting gamma rays or positrons.

From the article:

No one knows what dark matter is, since its presence is inferred only by its gravitational pull on normal matter. But researchers believe it is made up of particles that annihilate when they collide with each other. This produces gamma-ray photons that could be detected by telescopes such as Fermi (formerly called GLAST), which launched in June.

What empirical evidence shows that dark matter annihilates or that this annihilation produces gamma rays?

[edd]

There is no empirical evidence as such - that's why it's being looked for. There are however well motivated theoretical reasons for thinking that it might.

[edd]

Note that 'believe it is' in that article is journalistic exaggeration perhaps.

[Ziggurat]

The idea is to test hypotheses. Is this so unreasonable?

edd, perhaps you have not met Michael Mozina before. I think you should know a few things about him before you delve in too deeply. He's the owner of this web page:
http://www.thesurfaceofthesun.com/
Among other unconventional beliefs, he believes that the sun has a solid shell surface, and this web page advocates for this idea. Aside from the obvious mechanical instability of such a system, it also contradicts thermodynamics (http://forums.randi.org/showthread.php?p=4907711#post4907711). But Michael refuses to believe what is plain for everyone else to see.

Now my point here isn't actually to discuss the faults of Michael's ideas, because that's been done at length in other threads. We don't need to go over them here. But before you waste too much time trying to convince Michael about rather basic science issues, you should be aware of how futile the task is likely to be.

[edd]

Oh no, Michael and I have conversed here before :-)

I am just an optimist.

[sol invictus]

I'm curious why astronomers as a group are allowed to simply point at the sky and make stuff up in an ad hoc manner?

What do you think science is, Michael?

Let me explain this at a grade school level so you might get it. Scientists make stuff up. Then they test it. If it fails the test, they make something else up. If it passes it, they test it more.

What empirical evidence demonstrates that "dark matter" releases gamma rays or positrons?

Fermi's results?

Without such empirical validation, what it the world are they doing pointing at the sky with the Fermi telescope and claiming "dark matter did it" ?

How the hell are they going to get empirical validation if they don't look for it? And by the way, no one is claiming "dark matter did it". They're claiming that dark matter might have done it, and that certain DM models are consistent with Fermi's results (and others are not and are ruled out by them).

You know what that's called? It's called "science".

[Michael Mozina]

There is no empirical evidence as such - that's why it's being looked for. There are however well motivated theoretical reasons for thinking that it might.

Those "theoretical reasons" have not been verified empirically in any lab on Earth, so what's the point of trying to claim it happens "out there somewhere"? It seems to me that this is a *horrible* way to use Fermi data.

[Michael Mozina]

What do you think science is, Michael?

That seems to depend on who's doing the "science" evidently. What empirical "science" supports the claim that DM annihilates and produces gamma rays?

Let me explain this at a grade school level so you might get it.

Ah, the ever (not so clever) useless personal insult. Yawn.

Scientists make stuff up. Then they test it. If it fails the test, they make something else up. If it passes it, they test it more.

How did they "test" this annihilation claim exactly?

Fermi's results?

What makes you believe that Fermi sees anything other than standard gamma rays from standard sources (like our own sun)?

How the hell are they going to get empirical validation if they don't look for it?

There is no empirical validation possible in a non controlled pure observation! There is no way to achieve "empirical validation" outside of a real "experiment" with actual control mechanisms. Pointing at the sky with Fermi and claiming "dark matter did it" is not a form of "empirical verification" of the claim of DM annihilation.

And by the way, no one is claiming "dark matter did it". They're claiming that dark matter might have done it, and that certain DM models are consistent with Fermi's results (and others are not and are ruled out by them).

Anything and everything "might" do it, but only things that are KNOWN to release gamma rays. Claiming that "invisible elves might have done it" isn't a form of "science" only because you then see gamma rays in space.

You know what that's called? It's called "science".

I'm beginning to think that astronomers simply do not comprehend the difference between "science" and "make believe". As long as the math works out, you guys will accept anything and everything as a form of "science", with or without empirical support.

[edd]

If everything Fermi did had to be confirmed in a laboratory, I would suggest we should have spent the money elsewhere.

Personally I do not hold that all empirical evidence comes from an Earth-based laboratory.

[Ziggurat]

Those "theoretical reasons" have not been verified empirically in any lab on Earth, so what's the point of trying to claim it happens "out there somewhere"?

Same with General Relativity. Einstein had no way of testing it in a lab. So what was the point in looking at the orbit of Mercury?

[Dancing David]

Dark matter is something currently unexplained. That does not mean there are no tentative explanations. Some of these tentative explanations expect dark matter to annihilate with itself, but for the chance of this to be very low. However, we expect dark matter densities to peak strongly at the centre of galaxies and so there is a prediction that dark matter will annihilate at an appreciable rate at galactic cores.

One of the things Fermi is doing is looking for this. Having predictions and testing them is a good thing.

A negative result does not rule out dark matter but it constrains what it might be.

The idea is to test hypotheses. Is this so unreasonable?


Thanks Edd!

[Michael Mozina]

If everything Fermi did had to be confirmed in a laboratory, I would suggest we should have spent the money elsewhere.

Personally I do not hold that all empirical evidence comes from an Earth-based laboratory.

Put yourself in my shoes for a second Ed. *If* DM had already been shown to exist (say via LHC or some other collider experiment), *and* it had also been shown to annihilate and emit gamma rays, *then* I really would have nothing to complain about. Since steps A) and B) were never demonstrated, C) looks like pure "made up" speculation from where I sit. What empirical evidence actually supports the claim that DM emits *ANYTHING* let alone gamma rays? The whole thing is one big fallacy of affirming the consequent.

http://www.fallacyfiles.org/afthecon.html

The example they use is:

If it's raining then the streets are wet.
The streets are wet.
Therefore, it's raining.

In this case the circular feedback loop goes:

If DM exists in nature and it annihilates, it will produce gamma rays.
There are gamma rays in space.
Therefore DM annihilates and emits gamma rays.

[Michael Mozina]

Same with General Relativity. Einstein had no way of testing it in a lab. So what was the point in looking at the orbit of Mercury?

The empirical difference is that gravity actually shows up in empirical experiments on Earth, whereas the annihilation claim is pure speculation.

[Michael Mozina]

Dark matter is something currently unexplained. That does not mean there are no tentative explanations. Some of these tentative explanations expect dark matter to annihilate with itself, but for the chance of this to be very low. However, we expect dark matter densities to peak strongly at the centre of galaxies and so there is a prediction that dark matter will annihilate at an appreciable rate at galactic cores.

One of the things Fermi is doing is looking for this. Having predictions and testing them is a good thing.

A negative result does not rule out dark matter but it constrains what it might be.

The idea is to test hypotheses. Is this so unreasonable?

The "test" of that "string of assumptions" that you are calling a hypothesis is not reasonable. There's no evidence that exotic forms of matter exist. There's no evidence that DM annihilates to produce gamma rays or that it "collects" anywhere. There's no control mechanism in your "test".

The whole thing is one giant logical fallacy. If you knew for a fact that DM actually exists and does annihilate, then it might be "ok" to look for such signatures at the core of galaxies and such. Since every single one of these string of claims lacks any empirical support, the whole thing is a house of cards. You can't 'test' that theory in an uncontrolled observation. There could be any number of logical reasons why the core of a galaxy emits gamma rays, and no form of DM is known to emit gamma rays. Therefore the presence of gamma rays near the core of a galaxy is not automatic validation of this idea.

[Ziggurat]

The empirical difference is that gravity actually shows up in empirical experiments on Earth, whereas the annihilation claim is pure speculation.

Particle annihilation shows up in laboratories. Curved space does not.

[Ziggurat]

There's no control mechanism in your "test".

Einstein had no control mechanism for his tests of GR either.

[Michael Mozina]

http://arxiv.org/PS_cache/arxiv/pdf/0910/0910.2998v1.pdf

Here's a great example of that same fallacy in a paper by the way....

Searches for dark matter annihilation products are among the most exciting missions of the Fermi Gamma Ray Space Telescope (FGST).

Why? There's no evidence Fermi sees anything other than standard gamma rays from standard sources and lots of things emit gamma rays.

In particular, the FGST collaboration hopes to observe and identify gamma rays from dark matter annihilations occuring cosmologically [1], as well as within the Galactic Halo [2], dwarf galaxies [3], microhalos [4], and the inner region of the Milky Way [5].

Due to the very high densities of dark matter predicted to be present in the central region of our galaxy, the inner Milky Way is expected to be the single brightest source of dark matter annihilation radiation in the sky.

Here the authors simply "assume" that DM exists, that DM annihilates and emits gamma rays, and that exotic forms of DM are present in the inner part of the Milky way. None of these assumptions has been demonstrated. Any observations of gamma ray emissions we might come across in space are not automatic evidence of DM, they are simply "pure observations" of gamma rays. Period. Any claim about that gamma ray being associated with DM annihilation from a pure observation is purely arbitrary. Any number of things could generate gamma rays in and around a galaxy. In fact our own sun releases them on a regular basis. Gamma ray "observations" are *not* evidence of DM. Fermi sees gamma rays alright, but there is no evidence that any gamma rays come from DM. There is no control mechanism in a pure observation that could isolate a 'cause' of such emissions and there is no evidence that DM emits these wavelengths to begin with. Whatever "excitement" they might feel is purely arbitrary and entirely subjective because none of these scientists can isolate a cause from a pure observation.

[blutoski]

Put yourself in my shoes for a second Ed. *If* DM had already been shown to exist (say via LHC or some other collider experiment), *and* it had also been shown to annihilate and emit gamma rays, *then* I really would have nothing to complain about. Since steps A) and B) were never demonstrated, C) looks like pure "made up" speculation from where I sit. What empirical evidence actually supports the claim that DM emits *ANYTHING* let alone gamma rays? The whole thing is one big fallacy of affirming the consequent.

http://www.fallacyfiles.org/afthecon.html

The example they use is:

If it's raining then the streets are wet.
The streets are wet.
Therefore, it's raining.

In this case the circular feedback loop goes:

If DM exists in nature and it annihilates, it will produce gamma rays.
There are gamma rays in space.
Therefore DM annihilates and emits gamma rays.

Hate to burst your philosophical bubble, but affirming the consequent is key to how science is conducted. Your error is assuming deduction rather than induction. Science is inductive.

Here is a correction to demonstrate the scientific inquiry:


If DM exists in nature and it annihilates, we should see gamma rays from the direction where DM is suspected in excess of background rates.
There are gamma rays coming from the direction where DM is suspected in excess of background rates.
Therefore, the hypothesis is supported (until contradicted by sufficent replications)



Here is the purpose of such a process: refutation (denying the consequent)


If DM exists in nature and it annihilates, we should see gamma rays from the direction where DM is suspected in excess of background rates.
Gamma rays coming from the direction where DM is suspected in excess of background rates is NOT OBSERVED.
Therefore, the hypothesis is rejected (until contradicted by sufficent replications)


ie: it is untrue that all of science is a logical fallacy

[Michael Mozina]

Einstein had no control mechanism for his tests of GR either.

Gravity can easily be shown to exist in nature in any ordinary "experiment" with an ordinary control mechanism. The claim of existence of exotic forms of DM are pure speculation. Whereas some parts of Einstein's explanation of "gravity" may not have been easily verified on Earth, the existence of gravity was never in doubt.

[Michael Mozina]

Particle annihilation shows up in laboratories. Curved space does not.

DM doesn't show up in a lab. Period. Annihilation of normal forms of matter was never in doubt. Curved space does show up on Earth. Just trying jumping off the planet one time. :)

[Ziggurat]

DM doesn't show up in a lab. Period.

Sure it does. What do you think neutrinos are?

[blutoski]

Gravity can easily be shown to exist in nature in any ordinary "experiment" with an ordinary control mechanism. The claim of existence of exotic forms of DM are pure speculation. Whereas some parts of Einstein's explanation of "gravity" may not have been easily verified on Earth, the existence of gravity was never in doubt.

So?

Different hypotheses have different predictions. The nature of the prediction dictates how it is verified or disconfirmed.

[MattusMaximus]

edd, perhaps you have not met Michael Mozina before. I think you should know a few things about him before you delve in too deeply. He's the owner of this web page:
http://www.thesurfaceofthesun.com/
Among other unconventional beliefs, he believes that the sun has a solid shell surface, and this web page advocates for this idea. Aside from the obvious mechanical instability of such a system, it also contradicts thermodynamics (http://forums.randi.org/showthread.php?p=4907711#post4907711). But Michael refuses to believe what is plain for everyone else to see.

Now my point here isn't actually to discuss the faults of Michael's ideas, because that's been done at length in other threads. We don't need to go over them here. But before you waste too much time trying to convince Michael about rather basic science issues, you should be aware of how futile the task is likely to be.

I think what Zig is attempting to say can be summed up in one word: Troll.

[MattusMaximus]

DM doesn't show up in a lab. Period. Annihilation of normal forms of matter was never in doubt. Curved space does show up on Earth. Just trying jumping off the planet one time. :)

Mmmm... not necessarily. There are currently active searches in a variety of laboratories for DM. None have been successful yet, but then they haven't been looking too long either - just a few years. Recall that it took almost 40 years to detect neutrinos after they were predicted theoretically.

Because the observed astronomical evidence is so suggestive, I'm willing to reserve judgment on this particular point for some time. We'll see.

[Michael Mozina]

Hate to burst your philosophical bubble, but affirming the consequent is key to how science is conducted. Your error is assuming deduction rather than induction. Science is inductive.

In all my years of posting on websites, nobody has ever tried to claim that science was dependent upon a logical fallacy. That's a first. :)

Here is a correction to demonstrate the scientific inquiry:

If DM exists in nature

Then we should be able to demonstrate that claim in an empirical test with real control mechanisms. That was never done.

and it annihilates,

This is actually a SECOND assumption about the nature of a hypothetical entity. Since there is no evidence that exotic forms of matter exist, there's also no evidence that it annihilates. Both of these claims are "assumptions."

we should see gamma rays from the direction where DM is suspected in excess of background rates.

But where would that be? The fact that we can't identify all the mass in a galaxy is not evidence that new and exotic forms of matter are responsible for our failure. Most of the "missing mass" studies would suggest that the "missing mass" is mostly located on the outside edge of a galaxy rather than the core.

In order to know what is "excessive" in terms of rates, you would need to show what is "normal" without the presence of DM. How did you intend to do that?

There are gamma rays coming from the direction where DM is suspected in excess of background rates.

Cause is still "undetermined". There could be any number of other valid scientific reasons why gamma rays come from these areas.

Therefore, the hypothesis is supported (until contradicted by sufficent replications)

The problem is you never demonstrated exotic forms of matter exist, that they emit gamma rays, that it "collect" anywhere, nor show us what is "normal" without the presence of DM.

Here is the purpose of such a process: refutation (denying the consequent)

If DM exists in nature and it annihilates, we should see gamma rays from the direction where DM is suspected in excess of background rates.
Gamma rays coming from the direction where DM is suspected in excess of background rates is NOT OBSERVED.
Therefore, the hypothesis is rejected (until contradicted by sufficent replications)


The only thing that technically falsifies is the idea that DM emits visible gamma rays. That does not falsify the idea of "dark matter". It doesn't falsify the possibility that DM annihilates and emits gamma rays for that matter. It wouldn't falsify anything other than the single belief that we should "see" gamma rays from DM annihilation. That's not a real falsification mechanism for either the claim of exotic manner or the claim that these particles annihilate each other, so what have you actually falsified? The only thing you might falsify that way is the belief we should be able to "observe" them. The annihilation could occur inside of suns for instance and never be seen.

ie: it is untrue that all of science is a logical fallacy

FYI I didn't claim "all of science" is based upon a logical fallacy, I said *THIS* claim is based on a logical fallacy. Big difference.

[MattusMaximus]

Sure it does. What do you think neutrinos are?

Are neutrinos a leading candidate for DM? Just wondering.

[Michael Mozina]

So?

Different hypotheses have different predictions. The nature of the prediction dictates how it is verified or disconfirmed.

Please read my last response to your previous post and tell me how that particular "test" can be used to falsify either the claim of the existence of DM or the annihilation claim?

[Michael Mozina]

Are neutrinos a leading candidate for DM? Just wondering.

Not in this case.. Neutrinos don't annihilate and release gamma rays. Neutrinos also enjoy empirical support so I'll be happy to let you claim that "missing mass" is related to neutrinos. I simply won't let you claim that neutrinos generate gamma rays without additional support.

[MattusMaximus]

Not in this case.. Neutrinos don't annihilate and release gamma rays. Neutrinos also enjoy empirical support so I'll be happy to let you claim that "missing mass" is related to neutrinos. I simply won't let you claim that neutrinos generate gamma rays without additional support.

Thanks, but I was talking to Zig.

[Ziggurat]

Are neutrinos a leading candidate for DM? Just wondering.

Neutrinos are dark matter, but not all dark matter needs to be neutrinos. There do not appear to be enough neutrinos to account for the observed mass of dark matter, so they likely make up only a small faction of dark matter.

[Michael Mozina]

Mmmm... not necessarily. There are currently active searches in a variety of laboratories for DM. None have been successful yet, but then they haven't been looking too long either - just a few years. Recall that it took almost 40 years to detect neutrinos after they were predicted theoretically.

Whereas we knew and know exactly where neutrinos come from, where does DM come from?

Because the observed astronomical evidence is so suggestive, I'm willing to reserve judgment on this particular point for some time. We'll see.

I'm willing to "wait and see" what the future holds, but I have no reason to believe that exotic forms of matter exist in the first place, I have no reason to believe it emits gamma rays, and I have no reason to believe it collects near the center of galaxies. It's one thing to "reserve judgment" about the existence of something, but it's quite another thing to "reserve judgment" about the way that theory is already being abused by astronomers. It's impossible to verify or falsify the existence of something based upon a pure observation and no control mechanism. Anything could release gamma rays from a galaxy. What evidence is there that any type of gamma ray *could* be caused by "dark matter"?

[Michael Mozina]

Neutrinos are dark matter, but not all dark matter needs to be neutrinos. There do not appear to be enough neutrinos to account for the observed mass of dark matter, so they likely make up only a small faction of dark matter.

For the record, I have absolutely no problem with claiming that the "missing mass" might be related to neutrinos. In this case however we are not talking about neutrinos evidently because they cannot and do not release gamma rays when they "annihilate".

[MattusMaximus]

Neutrinos are dark matter, but not all dark matter needs to be neutrinos. There do not appear to be enough neutrinos to account for the observed mass of dark matter, so they likely make up only a small faction of dark matter.

Ah, I understand what you're saying now. Got it. Thanks. :)

[MattusMaximus]

Whereas we knew and know exactly where neutrinos come from, where does DM come from?

I'm willing to "wait and see" what the future holds, but I have no reason to believe that exotic forms of matter exist in the first place, I have no reason to believe it emits gamma rays, and I have no reason to believe it collects near the center of galaxies. It's one thing to "reserve judgment" about the existence of something, but it's quite another thing to "reserve judgment" about the way that theory is already being abused by astronomers. It's impossible to verify or falsify the existence of something based upon a pure observation and no control mechanism. Anything could release gamma rays from a galaxy. What evidence is there than any gamma ray *could* be caused by "dark matter"?

You do realize that I'm not interested in talking with you, right?

[Ziggurat]

It's impossible to verify or falsify the existence of something based upon a pure observation and no control mechanism.

Nonsense. Just look up at the sky sometime. The existence of the stars, the planets, the moon, and even the sun are all based upon pure observation. No control mechanism is needed.

[Ziggurat]

In this case however we are not talking about neutrinos evidently because they cannot and do not release gamma rays when they "annihilate".

Why on earth do you say that?

[Michael Mozina]

You do realize that I'm not interested in talking with you, right?

Yet you are posting here anyway and have the nerve to call *me* a "troll"? Tsk, tsk.

[MattusMaximus]

Yet you are posting here anyway and have the nerve to call *me* a "troll"? Tsk, tsk.

I am merely addressing what I consider to be erroneous arguments. Don't mistake that for me caring what you think. I don't.

[Michael Mozina]

Why on earth do you say that?

What empirical evidence can you provide to demonstrate that neutrinos annihilate one another and release gamma rays in that process?

[Michael Mozina]

I am merely addressing what I consider to be erroneous arguments. Don't mistake that for me caring what you think. I don't.

Ditto. :)

[Ziggurat]

What empirical evidence can you provide to demonstrate that neutrinos annihilate one another and release gamma rays in that process?

What else would they produce in an annihilation? The process should conserve energy, should it not?

And recall what you said: "they cannot and do not release gamma rays when they "annihilate"." As any idiot knows, absence of evidence is not evidence of absence, so regardless of whether or not we've seen neutrinos do that, where's the evidence that they cannot? That we haven't seen it? That only shows that it's at least rare, but considering the low neutrino-matter cross section, we should rather expect that neutrino-neutrino annihilations should be rare.

[Michael Mozina]

What else would they produce in an annihilation? The process should conserve energy, should it not?

And recall what you said: "they cannot and do not release gamma rays when they "annihilate"." As any idiot knows, absence of evidence is not evidence of absence, so regardless of whether or not we've seen neutrinos do that, where's the evidence that they cannot? That we haven't seen it? That only shows that it's at least rare, but considering the low neutrino-matter cross section, we should rather expect that neutrino-neutrino annihilations should be rare.

Shall I take that to mean: "None"?

[Ziggurat]

Shall I take that to mean: "None"?

Take it to mean whatever you want it to. You will anyways. But you seem to have missed the fact that you moved the goalpost from neutrinos being unable to annihilate and produce gamma rays to there being no evidence that they do. You can pretend all you want to that these are the same claims, but everyone else can recognize that they are not.

[Michael Mozina]

Take it to mean whatever you want it to. You will anyways. But you seem to have missed the fact that you moved the goalpost from neutrinos being unable to annihilate and produce gamma rays to there being no evidence that they do. You can pretend all you want to that these are the same claims, but everyone else can recognize that they are not.

Well, in fairness I should have said (was actually thinking) that they don't release positrons. That was the claim being made in the article I read this morning that "set me off" and why I started this thread to begin with.

http://blogs.discovermagazine.com/cosmicvariance/2009/05/04/fermi-waffles-on-dark-matter/

[blutoski]

In all my years of posting on websites, nobody has ever tried to claim that science was dependent upon a logical fallacy. That's a first. :)

I didn't either. It's clear that you do not understand the difference between deduction and induction.

In fact, I said this explicitly.

Since science is the inductive process of testing hypotheses to strenghten their acceptance, and since the purpose of every experiment is to deny or confirm the consequent, the only one here claiming that science is based on a fallacy is yourself.

Show me an experiment that isn't structured in the form of "If A then B"!





Then we should be able to demonstrate that claim in an empirical test with real control mechanisms. That was never done.

You have a different definition of 'empirical' than scientists do.

Regardless: no. There is no need for local experiments, although it can be nice to reinforce other findings.





This is actually a SECOND assumption about the nature of a hypothetical entity. Since there is no evidence that exotic forms of matter exist, there's also no evidence that it annihilates. Both of these claims are "assumptions."

Yes. It seems we are in agreement.











Cause is still "undetermined". There could be any number of other valid scientific reasons why gamma rays come from these areas.

Of course.





The problem is you never demonstrated exotic forms of matter exist, that they emit gamma rays, that it "collect" anywhere, nor show us what is "normal" without the presence of DM.

I understand that you consider it a problem. You understand that scientists disagree, right?







The only thing that technically falsifies is the idea that DM emits visible gamma rays. That does not falsify the idea of "dark matter". It doesn't falsify the possibility that DM annihilates and emits gamma rays for that matter. It wouldn't falsify anything other than the single belief that we should "see" gamma rays from DM annihilation. That's not a real falsification mechanism for either the claim of exotic manner or the claim that these particles annihilate each other, so what have you actually falsified? The only thing you might falsify that way is the belief we should be able to "observe" them. The annihilation could occur inside of suns for instance and never be seen.

That's right.



FYI I didn't claim "all of science" is based upon a logical fallacy, I said *THIS* claim is based on a logical fallacy. Big difference.

Every experiment is of the format "If A then B" testing for B. When we get B, we say the hypothesis is supported (not 'proven'). This is affirming the consequent. When we get ~B we say the null hypothesis is supported (~A).

Every experiment follows the same format. Your error was not understanding induction, and you misrepresented the nature of this experiment as deductive. If it had been deductive, then it would have been fallacious. But it is not: it is a scientific experiment, inductive, and not (necessarily) a fallacious reasoning.

[sol invictus]

Well, in fairness I should have said (was actually thinking) that they don't release positrons. That was the claim being made in the article I read this morning that "set me off" and why I started this thread to begin with.

http://blogs.discovermagazine.com/cosmicvariance/2009/05/04/fermi-waffles-on-dark-matter/

It's a shame you're so completely unreasonable, Michael, because this is actually an interesting topic. Contrary to your ridiculous assertions, this kind of data is exactly the kind of thing that leads to major scientific advances (whether it will in this case remains to be seen). The discovery of the cosmic microwave background and the solar neutrino deficit are two excellent examples of things like this in the recent past.

Fermi has confirmed that there is an excess of positrons over the expected background. That means one of three things:

1) DM annihilations are producing the excess, or
2) something else previously unknown is producing the excess, or
3) the experiment is mis-calibrated, or the result is a coincidence

How can we differentiate between these?

3) is tough to say much about if you're not on the experiment, but since the results go in the same direction as previous experiments I'm inclined to dismiss it for now.

To confirm 1), we need first a model for DM that predicts the positron excess and also is consistent with everything else we know, and then we need some additional predictions from it to test. Many people are working on that.

To confirm 2) , we need a model for this other effect that matches everything else we know, preferably with some additional predictions to test. People are working on that too (pulsars are a strong possibility).

It's a mystery to me what it is that you think is wrong with this process. Not that it makes the slightest difference what some internet crank thinks, but it's curious that I honestly have absolutely no idea what your problem with it is.

[blutoski]

Please read my last response to your previous post and tell me how that particular "test" can be used to falsify either the claim of the existence of DM or the annihilation claim?

Unknown. I defer to astronomers.

My comment was about the philosophy underlying scientific investigation.

[Michael Mozina]

Show me an experiment that isn't structured in the form of "If A then B"!

Well, for starters, the argument in question isn't structured that way. It's structured:

If A (exotic forms of DM exist in nature) *AND* B (they emit gamma rays) *and* C (we observe gamma rays in space) then A+B=C.

It's along the lines of:

If invisible gnomes exist *AND* they emit gamma rays *AND* we see gamma rays in space, then invisible gnomes exist and they emit gamma rays in space. C is actually a given so anything we postulate as A and B will be "acceptable" by your logic.

Since A and B were never demonstrated, the argument is actually "If C (a given) then A and B". A and B can be anything.

In either case (inductive/deductive) logic if your premises are flawed, your argument is still invalid. A) was never demonstrated. B) was never demonstrated. C) is a given and it doesn't necessarily follow even if A) and B) are valid. C doesn't follow A or B nor is it demonstrated to be related to A or B.

Every experiment is of the format "If A then B" testing for B.

Not this one. This one is pure "junk science" that involve *MULTIPLE* assumptions. This is also not an "experiment" since there is not a single thing being "tested", nor any control mechanism. It's simply an observation of gamma rays. The cause of these observed emissions remains unknown.

When we get B, we say the hypothesis is supported (not 'proven'). This is affirming the consequent. When we get ~B we say the null hypothesis is supported (~A).

Where is the null hypothesis for A and B individually? There isn't one.

Every experiment follows the same format. Your error was not understanding induction, and you misrepresented the nature of this experiment as deductive. If it had been deductive, then it would have been fallacious. But it is not: it is a scientific experiment, inductive, and not (necessarily) a fallacious reasoning.

The argument is still fallacious reasoning and you're hiding the very serious flaws in the argument behind semantics IMO. There is no if A then B "experiment", in fact there is no "experiment" here at all. It's a simply an uncontrolled "observation" of gamma rays. Period. What you choose to attribute those emissions to is purely arbitrary in this case. There is no connection between gamma rays and DM. It's purely an ad hoc assertion.

[blutoski]

It's a mystery to me what it is that you think is wrong with this process. Not that it makes the slightest difference what some internet crank thinks, but it's curious that I honestly have absolutely no idea what your problem with it is.

There's an old Woody Allen joke about the difference between psychosis and neurosis.

Psychosis: "2 + 2 = 5."
Neurosis: "2 + 2 = 4. But I have serious issues with that."

[blutoski]

Well, for starters, the argument in question isn't structured that way. It's structured:

If A (exotic forms of DM exist in nature) *AND* B (they emit gamma rays) *and* C (we observe gamma rays in space) then A+B=C.

It's along the lines of:

If invisible gnomes exist *AND* they emit gamma rays *AND* we see gamma rays in space, then invisible gnomes exist and they emit gamma rays in space. C is actually a given so anything we postulate as A and B will be "acceptable" by your logic.

The argument is actually "If C (actually a given) then A and B".

In either case (inductive/deductive) logic if your premises are flawed, your argument is still invalid. A) was never demonstrated. B) was never demonstrated. C) is a given and it doesn't necessarily follow even if A) and B) are valid. C doesn't follow A or B nor is it demonstrated to be related to A or B.

An hypothesis can contain multiple assumptions. It's called substitution.

Let D be "If A and B and C"


If D then E
E (observed)
therefore D is supported


or

If D then E
~E (not observed)
therefore D is not supported


The observations may not be intended to resolve among the hypotheses' components.




Not this one. This one is pure "junk science" that involve *MULTIPLE* assumptions. This is also not an "experiment" since there is not a single thing being "tested", nor any control mechanism. It's simply an observation of gamma rays. The cause of these observed emissions remains unknown.

Yes, I think we understand your opinion on this. We're trying to understand how you come to it.




Where is the null hypothesis for A and B individually? There isn't one.

Probably not, no. Resolution would require further experiments. Looks like astronomers have their work cut out for them.

I'm not sure why these facts bother you.




The argument is still fallacious reasoning and you're hiding the very serious flaws in the argument behind semantics IMO. There is no if A then B "experiment", in fact there is no "experiment" here at all. It's a simply an uncontrolled "observation" of gamma rays. Period. What you choose to attribute those emissions to is purely arbitrary in this case. There is no connection between gamma rays and DM. It's purely an ad hoc assertion.

I'm not sure if you're using ad hoc correctly, either.

In any case, what it is is an hypothesis that appears to be testable, and it looks like you're upset about it. Beyond that, I'm not sure what's going on.

[Michael Mozina]

It's a shame you're so completely unreasonable, Michael, because this is actually an interesting topic.

Imagine me claiming you were being "unreasonable" for not accepting my "God emits gamma rays from space" theory. We observe gamma rays from space so God obviously did it. I'm not being "unreasonable", your logic is simply flawed.

Contrary to your ridiculous assertions, this kind of data is exactly the kind of thing that leads to major scientific advances (whether it will in this case remains to be seen). The discovery of the cosmic microwave background and the solar neutrino deficit are two excellent examples of things like this in the recent past.

Sorry, but your comparisons are simply invalid IMO. Neutrinos can actually be "measured" so that we can tell if there is an actual "deficit". What's "normal" as it relates to gamma ray emissions from a galaxy without DM? What is a "normal" amount DM gamma ray emissions?

Fermi has confirmed that there is an excess of positrons over the expected background. That means one of three things:

1) DM annihilations are producing the excess, or

That not even a valid option! What "experiment" demonstrates that DM releases positrons?

2) something else previously unknown is producing the excess, or

Since it can't be number 1, it must be number 2 or 3.

3) the experiment is mis-calibrated, or the result is a coincidence

How can we differentiate between these?

You can differentiate between 2 and 3 but not 1 and 2 because 1 isn't even a viable scientific option. Whereas electrical discharges can and do release gamma rays, "DM" never has. I might be able to create experiments that emit gamma rays from electricity, but I could never do so with DM because gamma ray emitting DM doesn't even exist as far as I know. Where can I even get a gram of "dark matter" to experiment with?

It's a mystery to me what it is that you think is wrong with this process.

What's wrong with this process is that you never demonstrated that item number one was even a valid scientific option, you *assumed* it was a valid possibility. You're willing to explore "other" possibilities but you never demonstrated that item number one was even *A* possibility. When considering other options you will likely only consider "realistic" options, but you never demonstrated that item number one was actually a valid option.

[Michael Mozina]

You have a different definition of 'empirical' than scientists do.

I don't think so, and I think I know how to demonstrate it to you.

Do you have "empirical" scientific evidence of "God"? If so, what is it, if not what definition of "empirical" are you using exactly?

[Michael Mozina]

An hypothesis can contain multiple assumptions. It's called substitution.

Let D be "If A and B and C"

Let A be "God", B be "God emits positrons", and C be "God emits them in space". Let D be "Michael's new theory". Let E be gamma ray emissions in space.

If D, then E. E is observed. Is D a valid theory?

[blutoski]

I don't think so, and I think I know how to demonstrate it to you.

Do you have "empirical" scientific evidence of "God"? If so, what is it, if not what definition of "empirical" are you using exactly?

As a scientist, I don't use it much at all in my work. That's why I'm confused about what looks like a confusing and unusual use of a particular word.

When I use it, it refers to data that results from observations.

Collecting information with a special telescope is precisely what I'd call an exercise in empiricism.

[blutoski]

Let A be "God", B be "God emits positrons", and C be "God emits them in space". Let D be "Michael's new theory". Let E be gamma ray emissions in space.

If D, then E. E is observed. Is D a valid theory?

It is supported by the observations, yes.

[Reality Check]

That not even a valid option! What "experiment" demonstrates that DM releases positrons?

No experiment demonstrates that dark matter releases positrons.

There is a theory that dark matter particles annihilate and emit electron/positron pairs. A good explanation of the analysis of the Fermi data is on Sean Carroll's Cosmic Variance blog: Has Fermi Seen New Evidence for Dark Matter? (http://blogs.discovermagazine.com/cosmicvariance/2009/10/28/has-fermi-seen-new-evidence-for-dark-matter/)
In English: if the dark matter is a weakly-interacting massive particle (WIMP), individual WIMPs should occsasionally annihilate with other WIMPs, giving off a bunch of particles, including electron/positron pairs as well as high-energy photons (gamma rays).

Basically if we look at a source of gamma rays like the center of the galaxy and eliminate all known sources of gamma rays then we are left with unknown sources of gamma rays. One of these unknown sources may be dark matter annihilation.
The paper notes that this excess agrees with what we expect from the excess in the WMAP data (the WMAP haze (http://blogs.discovermagazine.com/cosmicvariance/2008/08/28/seeing-the-sky-with-different-eyes/)). The authors in fact do not claim that their analysis is evidence for dark matter.

IMO, the title of the blog entry is wrong. It should be "Has Fermi Seen New Evidence for the Composition of Dark Matter?". The evidence for the existence of dark matter is very strong. But I will not go into it and derail this thread. This evidence has been supplied to you several times and you have ignored it. There is no reason to think that you will not do the same.

[Michael Mozina]

When I use it, it refers to data that results from observations.......

It is supported by the observations, yes.

So Fermi has observed "empirical" evidence of God?

[sol invictus]

What's wrong with this process is that you never demonstrated that item number one was even a valid scientific option, you *assumed* it was a valid possibility. You're willing to explore "other" possibilities but you never demonstrated that item number one was even *A* possibility.

How could a theory not be a "valid possibility" or "valid scientific option"? I suppose it could be logically inconsistent, but the theories at issue here are certainly logically consistent.

The essence of science, the whole point of it, is that you don't know in advance which theories are correct and which aren't. They're all "valid scientific options" until you collect some evidence. Then you use that evidence to rule out some, and then try to differentiate between those that remain standing.

If, like you, you exclude some theories based on your faith that they are "invalid", you're religious. And that's is what all the other threads you've been involved in have boiled down to as well - you're unwilling to accept science as a valid way of approaching the world. Instead, you substitute faith.

[Michael Mozina]

How could a theory not be a "valid possibility" or "valid scientific option"? I suppose it could be logically inconsistent, but the theories at issue here are certainly logically consistent.

It has nothing to do with logical consistency, it has to do with what can be shown to exist and emit positrons. DM does not exist as far as you can demonstrate. It has never released a single positron in the lab, so what makes you think it does so "out there somewhere"?

[sol invictus]

It has nothing to do with logical consistency,

OK.


it has to do with what can be shown to exist and emit positrons.

But these theories can be shown to exist and be correct (by collecting evidence), and in them the annihilation produces positrons (that's the whole point). So then what's the problem?

Not that that objection makes any sense, but it doesn't even apply to these theories.

DE does not exist as far as you can demonstrate. It has never released a single positron in the lab, so what makes you think it does so "out there somewhere"?

Why are you talking about DE?

Michael, this is really, really, really simple. There are some extra positrons coming from somewhere. We don't know from what. No matter what explanation is proposed, it will be something that has not been demonstrated yet (because if it had been, we'd know where they're coming from, but we don't).

So if your criterion is that we can only consider theories that have been shown to be correct in the lab, then we cannot consider any theory to explain the origin of these positrons.

If we followed your rules, science would stop. That's because your rules are the exact antithesis of science.

[Ziggurat]

DE does not exist as far as you can demonstrate. It has never released a single positron in the lab

We're not talking about dark energy, we're talking about dark matter.

[edd]

Are neutrinos a leading candidate for DM? Just wondering.

Neutrinos are 'hot' or at least 'warm'. Dark matter for cosmological purposes needs to be cold (hence CDM).

Basically, cold dark matter will sit and gather up in one place and help galaxies form and all that stuff. Neutrinos won't - they'll just whizz off at near light-speed.

[Michael Mozina]

But these theories can be shown to exist and be correct (by collecting evidence),

You cannot demonstrate that a new form of matter exists based on evidence you collected from a telescope. The most you could demonstrate is "missing mass".

and in them the annihilation produces positrons (that's the whole point). So then what's the problem?

The problem is you never demonstrated that DM exists or that it emits positrons! You simply *assumed* both of these things.

Why are you talking about DE?

My bad. It should have been "DM", not "DE".

Michael, this is really, really, really simple. There are some extra positrons coming from somewhere. We don't know from what. No matter what explanation is proposed, it will be something that has not been demonstrated yet (because if it had been, we'd know where they're coming from, but we don't).

Huh? Just because you don't know where they come from, that's not evidence that they come from "dark matter".

So if your criterion is that we can only consider theories that have been shown to be correct in the lab, then we cannot consider any theory to explain the origin of these positrons.

Positrons are clearly involved in ordinary matter and the sun emits wavelengths consistent with matter/antimatter annihilation. What's the need for 'dark matter' when there are billions of known sources for positron/electron annihilation that are already identified?

If we followed your rules, science would stop. That's because your rules are the exact antithesis of science.

No. My rules are the rules of empirical science. Answer that same question I posed earlier about Michael's new theory. Do we also have evidence of God?

[Michael Mozina]

We're not talking about dark energy, we're talking about dark matter.

Yes, I know. You guys just invented so many mythical dark entities it's hard to keep them straight. :)

[fuelair]

edd, perhaps you have not met Michael Mozina before. I think you should know a few things about him before you delve in too deeply. He's the owner of this web page:
http://www.thesurfaceofthesun.com/
Among other unconventional beliefs, he believes that the sun has a solid shell surface, and this web page advocates for this idea. Aside from the obvious mechanical instability of such a system, it also contradicts thermodynamics (http://forums.randi.org/showthread.php?p=4907711#post4907711). But Michael refuses to believe what is plain for everyone else to see.

Now my point here isn't actually to discuss the faults of Michael's ideas, because that's been done at length in other threads. We don't need to go over them here. But before you waste too much time trying to convince Michael about rather basic science issues, you should be aware of how futile the task is likely to be.

Ahhh, nut case. Never mind I'm outta here!!!

[Michael Mozina]

You know sol.....

You sort of sidestepped that last question based on my typo.

DM has never been show to exist or release a single positron here on Earth, so what makes you think it exists and does that "out in space" somewhere?

[Michael Mozina]

Ahhh, nut case. Never mind I'm outta here!!!

Sure, you guys are peddling three forms of invisible metaphysical buddies, and *I'm* the nutcase. :)

[sol invictus]

You cannot demonstrate that a new form of matter exists based on evidence you collected from a telescope. The most you could demonstrate is "missing mass".

You're totally wrong as always, but in this case it doesn't matter. Many - perhaps all - of the theories we're discussing can be tested by future colliders, and some will be by the LHC.


The problem is you never demonstrated that DM exists or that it emits positrons! You simply *assumed* both of these things.


That's the way science works, Michael. What was the very first step in the scientific method as it was taught to you in grade school? I'll remind you: formulate a hypothesis.


Huh? Just because you don't know where they come from, that's not evidence that they come from "dark matter".


That is not a response to my comment. Please read it again.


Positrons are clearly involved in ordinary matter

What? No they're not.


and the sun emits wavelengths consistent with matter/antimatter annihilation.

What??

What's the need for 'dark matter' when there are billions of known sources for positron/electron annihilation that are already identified?


We're talking about excess positrons. But anyway, the reason is the known sources don't add up to enough to explain the data.


No. My rules are the rules of empirical science. Answer that same question I posed earlier about Michael's new theory. Do we also have evidence of God?

As far as I can tell, you're simply insane. Nothing you say makes sense to anyone else. That's a good sign you're crazy.

[Michael Mozina]

You're totally wrong as always, but in this case it doesn't matter. Many - perhaps all - of the theories we're discussing can be tested by future colliders, and some will be by the LHC.

Oddly enough we both agree that these would be legitimate "experiments" that could actually "test" such a theory. Of course by that logic it's been "tested" by other collider experiments too and so far - nothing.

That's the way science works, Michael. What was the very first step in the scientific method as it was taught to you in grade school? I'll remind you: formulate a hypothesis.

So by your logic, you God theory is also a great example of the "scientific method" in action, and we now have evidence of God?


What? No they're not.

Really? It's just a fluke that they are able to form subatomic particles with them (and electrons) in the lab?
http://en.wikipedia.org/wiki/Large_Electron%E2%80%93Positron_Collider

What??

Oh for crying out loud.....
http://www.iop.org/EJ/article/1538-4357/615/2/L169/18834.web.pdf?request-id=95cf3135-0485-4213-9c8e-e8a01297d0d8

[Reality Check]

You cannot demonstrate that a new form of matter exists based on evidence you collected from a telescope. The most you could demonstrate is "missing mass".
Scientists can demonstrate that a new form of matter exists based on evidence they have collected from telescopes.

As you have been told several times and are persistently ignoring: they observe colliding galactic clusters and see that there are two kinds of matter there. One kind is matter that interacts strongly, i.e. normal matter. Another kind is is not interacting much (if at all), i.e. dark matter.
If you want to continue this discussion then it should be in the previous thread where you stated this "missing matter" stuff. (http://forums.randi.org/showpost.php?p=5257138&postcount=2594)

[Reality Check]

Sure, you guys are peddling three forms of invisible metaphysical buddies, and *I'm* the nutcase. :)
We guys are pedding 2 scientific obsersverations (dark matter and dark energy) and a scientific theory that matches observations (inflation).
You are the nutcase whose idea explicitly violates the laws of themodynamics. For those unaware of the non-science in his idea have a look at the list of outstanding questions for Michael Mozina (http://forums.randi.org/showpost.php?p=5257182&postcount=1752) in the "Electric Universe theories here" thread.

[Tubbythin]

I'm willing to "wait and see" what the future holds, but I have no reason to believe that exotic forms of matter exist in the first place, I have no reason to believe it emits gamma rays, and I have no reason to believe it collects near the center of galaxies.

You don't believe in the existence of exotic forms of matter?
Not the lambda particle?
Not the eta meson or the J/psi?
Not the tau lepton?
Not positronium or muonium?
How about antihydrogen?
10He, 11Li?

[sol invictus]

Oddly enough we both agree that these would be legitimate "experiments" that could actually "test" such a theory. Of course by that logic it's been "tested" by other collider experiments too and so far - nothing.

Nope, they haven't been tested.


So by your logic, you God theory is also a great example of the "scientific method" in action, and we now have evidence of God?


What?


Really? It's just a fluke that they are able to form subatomic particles with them (and electrons) in the lab?
http://en.wikipedia.org/wiki/Large_Electron%E2%80%93Positron_Collider


What?


Oh for crying out loud.....
http://www.iop.org/EJ/article/1538-4357/615/2/L169/18834.web.pdf?request-id=95cf3135-0485-4213-9c8e-e8a01297d0d8

Which has to do with this topic.... how?

[Reality Check]

So by your logic, you God theory is also a great example of the "scientific method" in action, and we now have evidence of God?
Actually it is your logic that by replacing the phrase "dark matter" with the word "God" the scientific method states that the evidence of dark matter is evidence of God.
I do not know the name for this logical fallacy but it is a very bad one. You can replace the phrase "dark matter" with anything and get the same result, e.g. there is evidence for "Alffsrwbhv"!
Your post was:
Let A be "God", B be "God emits positrons", and C be "God emits them in space". Let D be "Michael's new theory". Let E be gamma ray emissions in space.

If D, then E. E is observed. Is D a valid theory?

Let A be "Alffsrwbhv", B be "Alffsrwbhv emits positrons", and C be "Alffsrwbhv emits them in space". Let D be "Michael's new theory". Let E be gamma ray emissions in space.
Let A be "rock", B be "rock emits positrons", and C be "rock emits them in space". Let D be "Michael's new theory". Let E be gamma ray emissions in space.
Let A be "Michael Mozina", B be "Michael Mozina emits positrons", and C be "Michael Mozina emits them in space". Let D be "Michael's new theory". Let E be gamma ray emissions in space.
etc.

[Humanzee]

Is this about the scientific method or just DM? If its about DM then what is it that bothers you so much MM? It seems to me scientists are trying to find the answer to what appears to be a large amount of missing mass in the universe. How can this looking be wrong?

[Michael Mozina]

Is this about the scientific method or just DM?

Evidently it's about DM. There's nothing wrong with the scientific method, just the fact that astronomers skirt around it.

If its about DM then what is it that bothers you so much MM? It seems to me scientists are trying to find the answer to what appears to be a large amount of missing mass in the universe. How can this looking be wrong?

IMO there is absolutely nothing wrong with noticing that we have a "missing mass" problem. There's a lot wrong with trying to stuff those gaps with metaphysical band-aids however.

FYI, I didn't actually have any trouble with the way "dark matter" was presented to me in school (mainly a MACHO orientation). It's only recently that astronomers have started making up exotic and unsupported "properties" of DM in a purely ad hoc manner. Today's "new and improved" DM does magic tricks. It evidently passes right through normal matter. It supposedly emits gamma rays when it feels like it. It now supposedly has a 'half life". There simply no end to the ad hoc properties they now assign to DM. As long as they can simply "make up" whatever property they like, and never have to demonstrate it empirically, they can point at the sky and claim "my new made up property of DM did it". Anything and everything observed in space is now being used as supporting evidence of some exotic property of "dark matter". Baloney.

[Michael Mozina]

Actually it is your logic that by replacing the phrase "dark matter" with the word "God" the scientific method states that the evidence of dark matter is evidence of God.

I used exactly the same logic you did! I took an ordinary observation and turned it into "evidence" of whatever I want.

I do not know the name for this logical fallacy but it is a very bad one.

I already told you the name of the fallacy. It's called "affirming the consequent". You're right, it's a "bad" one.

You can replace the phrase "dark matter" with anything and get the same result, e.g. there is evidence for "Alffsrwbhv"!

Gah! That's my whole point!

[Michael Mozina]

Nope, they haven't been tested.

At least we both agree there is a logical way to do so.

What?

What?

Which has to do with this topic.... how?

Holy Cow. There are hundreds of billions of confirmed sources for annihilation signatures in a galaxy! They are called "suns". What makes you think "DM did it"?

[Davidlpf]

I'm curious why astronomers as a group are allowed to simply point at the sky and make stuff up in an ad hoc manner? What empirical evidence demonstrates that "dark matter" releases gamma rays or positrons? Without such empirical validation, what it the world are they doing pointing at the sky with the Fermi telescope and claiming "dark matter did it" ?

You kind of started the insults in your first post so stop trying to point fingers at everywhere else.

Theorists thought a part of dark matter would emit gamma ray bursts. They got others to build observatory to look for it. They found bursts where the scientists thought the bursts would be, so more evidence for dark matter. They are not saying it has to be dark matter, it is just more evidence for dark matter.

[Reality Check]

I used exactly the same logic you did! I took an ordinary observation and turned it into "evidence" of whatever I want.

I already told you the name of the fallacy. It's called "affirming the consequent". You're right, it's a "bad" one.

Gah! That's my whole point!
Then you are wrong.
Affirming the consequent (http://en.wikipedia.org/wiki/Affirming_the_consequent)


Affirming the consequent, sometimes called converse error, is a formal fallacy, committed by reasoning in the form:
If P, then Q.
Q.
Therefore, P.
Arguments of this form are invalid, in that the conclusion (3) does not have to follow even when statements 1 and 2 are true. The simple reason for this is that P was never asserted as the only sufficient condition for Q, so, in general, any number of other factors could account for Q (while P was false).
The name affirming the consequent derives from the premise Q, which affirms the "then" clause of the conditional premise.
One way to demonstrate the invalidity of this argument form is with a counterexample with true premises but an obviously false conclusion. For example:
If Bill Gates owns Fort Knox, then he is rich.
Bill Gates is rich.
Therefore, Bill Gates owns Fort Knox.
Owning Fort Knox is not the only way to be rich. There are any number of other ways to be rich.

Nobody asserts that the Fermi data can only be produced by dark matter.
What they assert is that all known sources of the gamma rays have been eliminated (including the hundreds of billions of confirmed sources for annihilation signatures in a galaxy called "suns"!). That leaves unknown sources of gamma rays. Dark matter is one of the ways that the excess gamma rays may have been produced.

The last step in the fallacy is missing. It is not "Therefore, P". The last step in the logic used in this case is "Maybe, P (among other possibilities)".

[Michael Mozina]

You kind of started the insults in your first post so stop trying to point fingers at everywhere else.

Okey-dokey.

Theorists thought a part of dark matter would emit gamma ray bursts.

Ok, but why? Based on what empirical evidence did they theorize that DM emits gamma rays? How did they confirm that theory prior to pointing at the sky?

They got others to build observatory to look for it. They found bursts where the scientists thought the bursts would be, so more evidence for dark matter. They are not saying it has to be dark matter, it is just more evidence for dark matter.

http://www.nasa.gov/images/content/397293main_Fermi_1_year_revised.jpg

The problem is that common, ordinary suns are a known and demonstrated source of annihilation emissions and they too are spread around the whole galaxy. Coincidentally (actually not) Fermi does see gamma ray emissions coming from our whole galaxy, not just the core. What makes an exotic "dark matter" theory a "better" explanation than the obvious one (suns) to explain ordinary positron/electron annihilation?

[Michael Mozina]

Nobody asserts that the Fermi data can only be produced by dark matter.

Gah! You can't even demonstrate that dark matter *DOES* actually do what you claim it does and that it's even a logical option!

What they assert is that all known sources of the gamma rays have been eliminated (including the hundreds of billions of confirmed sources for annihilation signatures in a galaxy called "suns"!). That leaves unknown sources of gamma rays.

Hell, until tonight I don't think sol even realized that suns emitted annihilation signatures! What makes you think I have any confidence that astronomers actually eliminated suns from consideration? This industry has an extremely bad habit of eliminating logical possibilities based on absurdly weak arguments.

Dark matter is one of the ways that the excess gamma rays may have been produced.

Let me see you empirically demonstrate that claim *WITHOUT* affirming the consequent.

The last step in the fallacy is missing. It is not "Therefore, P". It is "Maybe, P (among other possibilities)".

"Maybe P" is a "belief" that is born of "pure faith" because you can't demonstrate that DM exists, that it emits *ANY* form of light, let alone gamma rays. The 'maybe p" claim was pure ad hoc speculation in the first place. It's like me claiming that "maybe God did it" and therefore my argument is completely "Ok" so long as I remember to use the term "maybe". Maybe you forgot to demonstrate that DM exists. Maybe you forgot to demonstrate it emits anything, particularly gamma rays. Maybe you forgot to demonstrate your claim that it's even a legitimate "maybe".

[temporalillusion]

Is this about the scientific method or just DM?

Every MM thread is about the scientific method. Ultimately it boils down to "if it hasn't been tested in a lab it doesn't exist", MM rejects natural experiments as valid science.

So while everyone goes round and round about specific things, it always comes back to that.

[Reality Check]

Gah! You can't even demonstrate that it dark matter *DOES* actually do what you claim it does!

Gah! What do you mean? What do you think scientists claim that dark matter *DOES*?

The claim in this case is that dark matter may be a weakly interacting massive particle that may annihilate producing elections and positrons that would then produce gamma rays. This might be detected by Fermi if we subtract all other known mechanisms for generating gamma-rays at the energies observed by Fermi. But Fermi might be detecting another mechanism producing the same gamma rays.
I do not claim that dark matter is weakly interacting massive particles that do annihilate producing elections and positrons that would then produce gamma rays.


Let me see you actually demonstrate that claim *WITHOUT* affirming the consequent.

I just did but lets make it clearer: "Maybe P or X or Y or Z or ..." is the last assertion.


"Maybe P" is a "belief" that is born of "pure faith" because you can't demonstrate that DM exists, that it emits *ANY* form of light, let alone gamma rays. The 'maybe p" claim was pure ad hoc speculation in the first place. It's like me claiming that "maybe God did it" and therefore my argument is completely "Ok" so long as I remember to use the term "maybe". Maybe you forgot to demonstrate that DM exists. Maybe you forgot to demonstrate it emits anything, particularly gamma rays. Maybe you forgot to demonstrate your claim that it's even a legitimate "maybe".
"Maybe P (among other possibilities)", i.e. "Maybe P or X or Y or Z or ...", is exactly what astronomers assert. Thus there is no fallacy and you are wrong in thinking that there is a fallacy. The fallacy only exists if there can only one conclusion ("Therefore P").

ETA:
Actually the conclusion of the authors is closer to "Therefore, this is new physics, such as the decay or annihilation of dark matter; or new astrophysics".
Using the the Wikipedia article example:

If Bill Gates owns Fort Knox, then he is rich.
Bill Gates is rich.
"Therefore, Bill Gates owns Fort Knox." produces the fallacy.
"Therefore, Bill Gates owns Fort Knox or has some other source of wealth" does not produce the fallacy.

Dark matter is a valid possibility because the observational evidence for the existence of dark matter (http://en.wikipedia.org/wiki/Dark_matter#Observational_evidence) is very strong.

It looks like the gamma rays emitted from stars are either too weak or at the wrong energies. From the paper:
The Fermi Haze: A Gamma-Ray Counterpart to the Microwave Haze (http://arxiv.org/abs/0910.4583)


There are three well-known mechanisms for generating gamma-rays at the energies observed by Fermi. First, at low (1 GeV) energies, gamma-ray emission is dominated by photons produced by the decay of pi0 particles generated in the collisions of cosmic ray protons (which have been accelerated by SNe) with gas and dust in the ISM. Second, relativistic electrons colliding with nuclei (mostly protons) in the ISM produce bremsstrahlung radiation. Finally, those same electrons interact with the interstellar radiation field (ISRF) and inverse Compton scatter (ICS) CMB, infrared, and optical photons up to gamma-ray energies.


They then go onto subtract these contributions from the Fermi data.



If you have a citation that states that the Fermi data includes contributions from stars then I would be interested in it.

[Michael Mozina]

http://www.nasa.gov/mp4/397394main_NEW_Blazar_Galactic__NP_with_labels_640 x480.mp4

If you watch the right side of this Fermi video, you'll notice a bright object moving from the top toward the bottom of the image. Would anyone care to guess what that moving bright spot corresponds to?

[Michael Mozina]

Gah! What do you mean? What do you think scientists claim that dark matter *DOES*?

They claim that "dark matter" emits gamma rays. Care to demonstrate that claim without relying on a logical fallacy or an act of pure faith?

The claim in this case is that dark matter may be a weakly interacting massive particle that may annihilate producing elections and positrons that would then produce gamma rays. This might be detected by Fermi if we subtract all other known mechanisms for generating gamma-rays at the energies observed by Fermi. But Fermi might be detecting another mechanism producing the same gamma rays.
I do not claim that dark matter is weakly interacting massive particles that do annihilate producing elections and positrons that would then produce gamma rays.

So let me understand your logic. As long as you toss in enough disclaimers you figure that is going to make it better? Well, in my hypothetical theory, "God" "may" exist and "may" emit gamma rays and "may" do so in space. Does that make my "God did it" theory more palatable to you personally?

If you have a citation that states that the Fermi data includes contributions from stars then I would be interested in it.

Great. How about identifying that object for us on the right side of that Fermi movie that travels from top to the bottom of the image during the movie.

http://www.nasa.gov/mission_pages/GLAST/news/first_year.html
http://www.nasa.gov/mp4/397394main_NEW_Blazar_Galactic__NP_with_labels_640 x480.mp4

[Davidlpf]

Why can there not be gamma rays produced by stars and DM? Because in some peoples minds it has to be one or the other. It is not the scientist claim all the positrons are coming from dark matter but just the excess of what they were expecting if it was just coming from stars alone.

[Michael Mozina]

Why can there not be gamma rays produced by stars and DM?

Because DM has never been shown to actually emit gamma rays in the first place!

Because in some peoples minds it has to be one or the other. It is not the scientist claim all the positrons are coming from dark matter but just the excess of what they were expecting if it was just coming from stars alone.

I'm willing to let you posit *ANY* and *multiple* "known" source(s) of gamma rays, including electrical discharges, the one thing in nature that has been shown to emit gamma rays right here on Earth. What I won't let you do is simply *assume/claim* that DM had anything to do with it unless you can demonstrate that DM exists and actually emits gamma rays.

Here, I'll give you folks a hint about that moving arc on the right side of the image:

http://esciencenews.com/articles/2009/03/11/nasas.fermi.telescope.reveals.best.ever.view.gamma .ray.sky

The map includes one object familiar to everyone: the sun. "Because the sun appears to move against the background sky, it produces a faint arc across the upper right of the map," Michelson explained. During the next few years, as solar activity increases, scientists expect the sun to produce growing numbers of high-energy flares. "No other instrument will be able to observe solar flares in the LAT's energy range," he said.

[Michael Mozina]

Every MM thread is about the scientific method. Ultimately it boils down to "if it hasn't been tested in a lab it doesn't exist", MM rejects natural experiments as valid science.

So while everyone goes round and round about specific things, it always comes back to that.

Well, it does seem to always come back to the fact that astronomers cannot empirically demonstrate their claim and 96% of Lambda-CDM theory is based upon hypothetical entities. How is that my fault?

[Davidlpf]

I'm willing to let you posit *ANY* and *multiple* "known" source(s) of gamma rays, including electrical discharges, the one thing in nature that has been shown to emit gamma rays right here on Earth. What I won't let you do is simply *assume/claim* that DM had anything to do with it unless you can demonstrate that DM exists and actually emits gamma rays.





Electricity does produce gamma rays, but do you have proof that is causing gamma rays in space. It looks like you are jumping to conclusions. Scientists say there is something in space but they do not have proof of what exactly what it is. The gamma rays is just evidence of what it might be.

[Michael Mozina]

Electricity does produce gamma rays, but do you have proof that is causing gamma rays in space.

Well, since Earth is in fact located in "space" and gamma rays occur here on Earth and other planets, yes, as a matter of fact I have proof that discharges cause gamma rays in space.

It looks like you are jumping to conclusions.

Not me. I can see that sun traverse the Fermi image with my own eyes. I know for a fact that a sun will emit annihilation signatures. I know for a fact that discharges create gamma rays too. I have zero evidence that DM does exists or does squat in terms of gamma ray emissions.

Scientists say there is something in space but they do not have proof of what exactly what it is. The gamma rays is just evidence of what it might be.

The gamma rays "might be" caused by any KNOWN force of nature. It's not possible however for these wavelengths of light to have been created by dark matter because dark matter has never been shown to emit such wavelengths. My "God did it" theory is at least as "scientific" as any "dark matter did it" theory in that respect.

[Davidlpf]

Well, since Earth is in fact located in "space" and gamma rays occur here on Earth and other planets, yes, as a matter of fact I have proof that discharges cause gamma rays in space.
There is no evidence to back up that electricity are causing the ones being observed by fermi.
Not me. I can see that sun traverse the Fermi image with my own eyes. I know for a fact that a sun will emit annihilation signatures. I know for a fact that discharges create gamma rays too. I have zero evidence that DM does exists or does squat in terms of gamma ray emissions.

The sun does produce annihilation signatures but no one here has said the gamma ray bursts are created by DM. You are claiming that scientists claim all gamma ray bursts are created by DM and no one actually is. Matter/antimatter annihilation has been observed here on Earth and some nuclear processes in the sun can create positrons and electrons, so the most likely process to emit gamma rays is positron/electron annihilation.

The gamma ray emissions that scientist think are caused by DM are the excess that they expect from what the stars produce.

[Michael Mozina]

The sun does produce annihilation signatures but no one here has said the gamma ray bursts are created by DM. You are claiming that scientists claim all gamma ray bursts are created by DM and no one actually is.

Could you quote me where I actually stated that "scientists claim "all" gamma ray bursts are created by DM? That seems to be your misconception if that is how you interpret my statements. My complaint is not that scientists claimed that *ALL* gamma ray burst come from DM. My complaint is that they claimed that *ANY* gamma ray bursts come from DM because that claim has never been demonstrated empirically.

Matter/antimatter annihilation has been observed here on Earth and some nuclear processes in the sun can create positrons and electrons, so the most likely process to emit gamma rays is positron/electron annihilation.

Ok.

The gamma ray emissions that scientist think are caused by DM are the excess that they expect from what the stars produce.

What exactly do they "expect" and why? Wouldn't solar cycle changes and all sorts of unknown factors have some influence on these "expectations"? Since Fermi has only been in space for a little over a year, how exactly did they even decide what to "expect" from our own sun over a typical 11 year cycle?

The key issue here is that suns are a known source of annihilation signatures, and even planets can emit gamma rays from their atmosphere. Since there are literally hundreds of billions of stars and planets in a galaxy why do we need to look further than stars and planets and typical objects in space as a "source" of gamma rays? How do we even know what to "expect" in the first place?

[Reality Check]

They claim that "dark matter" emits gamma rays. Care to demonstrate that claim without relying on a logical fallacy or an act of pure faith?

There is a theory that dark matter may be made of particles that annihilates to electrons and positrons and that this produces gamma rays. There is no "demonstration" of this except a possibility that Fermi has detected these gamma rays.


So let me understand your logic. As long as you toss in enough disclaimers you figure that is going to make it better? Well, in my hypothetical theory, "God" "may" exist and "may" emit gamma rays and "may" do so in space. Does that make my "God did it" theory more palatable to you personally?

My logic is that you do not know what the authors of the paper acually said in their conclusion.
Their conclusion was not that dark matter emitted the gamma rays.

Their conclusion was that new physics (e.g. the decay or annihilation of dark matter) or new astrophysics is the mechanism producing the excess gamma rays.

So your original logic was wrong and there is no fallacy.


Great. How about identifying that object for us on the right side of that Fermi movie that travels from top to the bottom of the image during the movie.

http://www.nasa.gov/mission_pages/GLAST/news/first_year.html
http://www.nasa.gov/mp4/397394main_NEW_Blazar_Galactic__NP_with_labels_640 x480.mp4
It is the Sun.
Did you know that the Sun is a bit closer to us than other stars?
Have you heard of the inverse square rule for the intensity of radiation?

Fermi's Best-Ever Look at the Gamma-Ray Sky (http://www.nasa.gov/mission_pages/GLAST/news/gammaray_best.html)
The top five sources within our galaxy are:

The sun. Now near the minimum of its activity cycle, the sun would not be a particularly notable source except for one thing: It's the only one that moves across the sky. The sun's annual motion against the background sky is a reflection of Earth's orbit around the sun.

"The gamma rays Fermi now sees from the sun actually come from high-speed particles colliding with the sun's gas and light," Thompson notes. "The sun is only a gamma-ray source when there's a solar flare." During the next few years, as solar activity increases, scientists expect the sun to produce growing numbers of high-energy flares, and no other instrument will be able to observe them in the LAT's energy range.

You have still not produced the citation that I asked for:
If you have a citation that states that the Fermi data includes contributions from stars ( to be clear: the stars in the galaxy - not just our Sun or specific high energy sources) then I would be interested in it.

It is obvious that astronomers know about the various point sources (X-ray binaries, pulsars, etc.). Now show that the paper incorrectly ignored these.

ETA:
Found it! I remember reading something about point sources in the paper (http://arxiv.org/abs/0910.4583) and here it is:

In this fit, we mask out all of the Fermi 3-month point source catalog as well as the LMC, SMC,Orion-Barnard’s Loop, and NGC 5090.

And Apendex A is all about the effects of unresolved point sources! Itconcludes

As Fig. 13 shows, at low energies we find values of R consistent with a significant point source component (although the point source fraction cannot be precisely determined without knowing the luminosity function). Above 10 GeV, however, the value of R is consistent with entirely diffuse emission, and at 95% confidence, the fraction of emission from unresolved point sources cannot exceed ~ 5% and remain consistent with the measured value of R. Therefore,even for these conservative assumptions, the hard spectral shape of the Fermi haze cannot be caused by point source contamination.

[Davidlpf]

What would the 11 year cycle have to do with the particles created in the center of the sun?
I would imagine that scientist have modeled how many gamma rays would be produced by stars and other objects, so they would know if there are excess gamma rays.

[Reality Check]

What would the 11 year cycle have to do with the particles created in the center of the sun?
I would imagine that scientist have modeled how many gamma rays would be produced by stars and other objects, so they would know if there are excess gamma rays.
The situation is that solar gamma rays are produced in solar flares and so their intensity is cyclic.
As in MM's link:
ANNIHILATION RADIATION OBSERVATIONS: IMPLICATIONS FOR CONDITIONS IN THE FLARING SOLAR CHROMOSPHERE (http://www.iop.org/EJ/article/1538-4357/615/2/L169/18834.web.pdf?request-id=b25b169d-780f-41a7-ad90-c1976b769086)
Flare-accelerated ions interact with the solar atmosphere to produce radioactive nuclei (Kozlovsky et al. 1987) and pions (Murphy et al. 1987) that decay, yielding positrons. Positrons slow down by interactions with the ambient medium prior to directly annihilating with electrons or forming the hydrogenlike positronium atom. Direct annihilation and annihilation from the singlet state of positronium give rise to two 511 keV photons, while annihilation from the triplet state yields three photons with varying energies below 511 keV.
This means that the Sun is a strong point source of gamma radiation beacuse it is close to us. Other normal stars are not sources but there are the other strong point sources like pulsars and X-ray binaries.

I suspect that these point sources were ignored since the paper is analyzing the general radiation.

[Davidlpf]

The situation is that solar gamma rays are produced in solar flares and so their intensity is cyclic.
As in MM's link:
ANNIHILATION RADIATION OBSERVATIONS: IMPLICATIONS FOR CONDITIONS IN THE FLARING SOLAR CHROMOSPHERE (http://www.iop.org/EJ/article/1538-4357/615/2/L169/18834.web.pdf?request-id=b25b169d-780f-41a7-ad90-c1976b769086)

This means that the Sun is a strong point source of gamma radiation beacuse it is close to us. Other normal stars are not sources but there are the other strong point sources like pulsars and X-ray binaries.

I suspect that these point sources were ignored since the paper is analyzing the general radiation.
My bad. I should not try to a lot of things at once.

[Davidlpf]

But I stand on what I was saying that the scientists are just saying there is evidence pointing to a source of dark matter by the production of the excess gamma rays.

[Dancing David]

You cannot demonstrate that a new form of matter exists based on evidence you collected from a telescope.

Helium any one?

[Dancing David]

I used exactly the same logic you did! I took an ordinary observation and turned it into "evidence" of whatever I want.


Well you haven't provided much information on the framework for how God creates the gamma rays on positrons, now have you?

And why they would occur where they occur?

[sol invictus]

The gamma rays "might be" caused by any KNOWN force of nature.

Only if those known forces have been misunderstood. As has been explained to you repeatedly, the point is precisely is that known sources cannot account for the spectrum observed by these experiments.

It's not possible however for these wavelengths of light to have been created by dark matter because dark matter has never been shown to emit such wavelengths.

Something isn't possible because it hasn't been shown? That literally makes no sense.

My "God did it" theory is at least as "scientific" as any "dark matter did it" theory in that respect.

You could have a theory that says "there is a god and he makes this particular spectrum of gamma rays". Go ahead and construct it. If the spectrum god makes according to that theory agrees with Fermi, that's evidence for it - so yes, you're right, Fermi is evidence for a specific theory of god. Of course we also have a theory of dark matter that agrees with Fermi. So how to we compare the two? Answer: by counting the number of parameters, or alternatively by another measure of the complexity of the theory.

To be a contender, the theory has to be able to predict the results of all the experiments we might do. That means your theory about god also has to say how many neutrinos he makes, and how many CMB photons, what spectrum of galaxies, etc. etc. Once you put that all in you'll have an enormously complex theory, because you'll have to specify each of those independently. On the other hand I can write down this dark matter theory in a single line, using only a few parameters.

In a nutshell, that's the reason the DM theory is vastly preferred - it has far fewer parameters, it's coherent and much simpler, and it explains the available data just as well. (It's also falsifiable, but your god theory would be too if you specified it precisely enough.)

[Michael Mozina]

There is a theory that dark matter may be made of particles that annihilates to electrons and positrons and that this produces gamma rays. There is no "demonstration" of this except a possibility that Fermi has detected these gamma rays.

And since ordinary suns release these same exact gamma rays on a regular basis you have absolutely nothing to support your claim.

My logic is that you do not know what the authors of the paper acually said in their conclusion.
Their conclusion was not that dark matter emitted the gamma rays.

So what? Based on what evidence? Point at the sky claims?

Their conclusion was that new physics (e.g. the decay or annihilation of dark matter) or new astrophysics is the mechanism producing the excess gamma rays.

So your original logic was wrong and there is no fallacy.

The fact that these authors make exactly the same mistake you're making doesn't justify the error.

It is the Sun.

So suns are a perfectly "natural" source for such emissions and we have no need for anything exotic.

Did you know that the Sun is a bit closer to us than other stars?
Have you heard of the inverse square rule for the intensity of radiation?

Uh, yes, but what does that have to do with anything? You asked for evidence that Fermi could see a sun. I provided that evidence. Gamma rays are definitely coming from our sun and likely all suns in the galaxy. It's hardly a surprise then when we can observe the galaxy in gamma rays in a Fermi image.

[Michael Mozina]

Only if those known forces have been misunderstood.

That's pretty much a given. You seem to find it to be quite the revelation that stars even emitted annihilation signatures. The whole industry still *IGNORES* the role of electricity in space.

As has been explained to you repeatedly, the point is precisely is that known sources cannot account for the spectrum observed by these experiments.

How do you know that? Even assuming that was true, that is absolutely no excuse or justification for "making up" a mythical source of gamma rays.

Something isn't possible because it hasn't been shown? That literally makes no sense.

So "God did it" is perfectly acceptable to you as it relates to gamma ray emissions?

You could have a theory that says "there is a god and he makes this particular spectrum of gamma rays". Go ahead and construct it. If the spectrum god makes according to that theory agrees with Fermi, that's evidence for it - so yes, you're right, Fermi is evidence for a specific theory of god. Of course we also have a theory of dark matter that agrees with Fermi. So how to we compare the two? Answer: by counting the number of parameters, or alternatively by another measure of the complexity of the theory.

It's a push then because you have two unverified parameter (DM exists & DM emits gamma rays) as do I. So my God theory is evidently a "scientific solution" to this observation too?

To be a contender, the theory has to be able to predict the results of all the experiments we might do.

As long as I can "make it up" as I go and I never have to physically demonstrate it, it's no problem.

In a nutshell, that's the reason the DM theory is vastly preferred - it has far fewer parameters, it's coherent and much simpler, and it explains the available data just as well. (It's also falsifiable, but your god theory would be too if you specified it precisely enough.)

Assuming I ascribe "God" with every single parameter that you assign to 'dark matter', how exactly did you intend to falsify my God theory?

[Michael Mozina]

But I stand on what I was saying that the scientists are just saying there is evidence pointing to a source of dark matter by the production of the excess gamma rays.

*If* you could demonstrate that "dark matter" actually exists *and* you could demonstrate it emits gamma rays *THEN* (and only then) is it a viable possibility. Since nobody can show that DM exists or emits gamma rays, it's simply an ad hoc construct.

[sol invictus]

That's pretty much a given. You seem to find it to be quite the revelation that stars even emitted annihilation signatures. The whole industry still *IGNORES* the role of electricity in space.

That statement is simply incomprehensible. Nearly everything done in astrophysics directly concerns the role of "electricity" in space.


How do you know that?

If you'd read any of the relevant literature, you'd know. Are you saying you haven't?

Even assuming that was true, that is absolutely no excuse or justification for "making up" a mythical source of gamma rays.


Something has to explain the discrepancy. We've been over this - it's either something new, or it's something known but misunderstood. Both approaches are being pursued by many people.


It's a push then because you have two unverified parameter (DM exists & DM emits gamma rays) as do I. So my God theory is evidently a "scientific solution" to this observation too?


OK, you don't know what "parameter" means. Try looking at one of the models you find so hard to accept and you'll see what they are.


Assuming I ascribe "God" with every single parameter that you assign to 'dark matter', how exactly did you intend to falsify my God theory?

See above.

[Tubbythin]

*If* you could demonstrate that "dark matter" actually exists *and* you could demonstrate it emits gamma rays *THEN* (and only then) is it a viable possibility. Since nobody can show that DM exists or emits gamma rays, it's simply an ad hoc construct.

Er no. 20 years ago we couldn't show the top quark existed. It doesn't mean that 20 years ago the top quarks existence wasn't a viable possibility.

[Michael Mozina]

That statement is simply incomprehensible. Nearly everything done in astrophysics directly concerns the role of "electricity" in space.

So how about showing us a half dozen papers published in the APJ (or another mainstream publication) over the last few years that use the term "electricity" and "electrical discharge" in it. Electricity is the "evil" word in your industry. It's the forbidden topic. "Magnetic reconnection" is "ok". "Circuit reconnection" is *FORBIDDEN* lest thou be cast out of your religion. :) Go over and read the rules at Bad Astronomy about EU theory and tell me that "electricity" isn't the forbidden topic of astronomy today. Let's see those recent papers in some mainstream publications too.

If you'd read any of the relevant literature, you'd know. Are you saying you haven't?

All the literature I read uses stupid terms like "magnetic reconnection" and "dark yada yada yada". Never once do the mainstream publications print material related to electrical discharge theory as it relates to solar physics even though it's clear that discharges are occurring in the atmospheres of every major planet and body in the solar system.

Last time I saw nature create gamma rays here on Earth it was done with "electricity", not "magnetic reconnection". Now tell me what "caused" those annihilation signatures and where did those positrons come from?

Something has to explain the discrepancy. We've been over this - it's either something new, or it's something known but misunderstood. Both approaches are being pursued by many people.

Sure, *something* has to explain it, but we know for a fact that "electricity" already does that. Dark matter has *NEVER* been shown to emit gamma rays, whereas discharges in the Earth's atmosphere do it every single day. From an Occum's razor perspective, your "dark matter" deity thingy hasn't got a prayer's chance in hell. :)

OK, you don't know what "parameter" means. Try looking at one of the models you find so hard to accept and you'll see what they are.

Right, I write software for a living, but haven't a clue what a "parameter" might be.....

You cannot demonstrate "dark matter" exists anymore than I can demonstrate "God matter" exists or emits anything inside physical reality. Slapping math onto either term isn't going to justify the term via empirical physics. If I simply substitute the term "God matter" where you are using "Dark matter", it becomes a "religion" based purely on faith.

[Michael Mozina]

Er no. 20 years ago we couldn't show the top quark existed. It doesn't mean that 20 years ago the top quarks existence wasn't a viable possibility.

Anything and everything is a "possibility", but "probability" (I used the term "viable" in that sentence) is equally important. *Many* of the particles of the standard model had already been identified and confirmed 20 years ago. A few key pieces remained to be seen, and even today the Higgs Boson has yet to be observed in empirical experimentation. 20 years ago it was pretty clear the that the standard model did an excellent job "explaining" all the key elements of particle physics theory. (Note that SUSY particles aren't even a part of standard theory).

Whereas there was a "probability" that someone would eventually find the top quark 20 years ago, there's still no "probability' that any SUSY particle will EVER be found.

We point Rhessi at the Earth and we see gamma rays from discharges in the Earth's atmosphere. We point Rhessi at the sun and see annihilation wavelengths during flares. There are at least a half dozen possible "sources' of gamma rays in just this one solar system. No doubt when we look out at *hundreds of billions of solar systems in a galaxy* we will likely observe a lot of gamma rays. If we need more of them, all we have to do is turn up the "electricity" and a known source of gamma rays in nature will produce more gamma rays.

The "odds" of "dark matter" being responsible for gamma rays is one in a million at best. It's never been seen on Earth in a real experiment, not one single time. Gamma rays occur naturally here on Earth every single day due to "electricity". I don't need no stinking "dark matter" to explain gamma rays of any quantity.

If we take an Occum's razor to your argument, I'm afraid it's toast. There is a plentiful and abundant source of gamma rays to be found in simple "electricity".

[Tubbythin]

Anything and everything is a "possibility", but "probability" (I used the term "viable" in that sentence) is equally important. *Many* of the particles of the standard model had already been identified and confirmed 20 years ago. A few key pieces remained to be seen, and even today the Higgs Boson has yet to be observed in empirical experimentation. 20 years ago it was pretty clear the that the standard model did an excellent job "explaining" all the key elements of particle physics theory. (Note that SUSY particles aren't even a part of standard theory).

It certainly doesn't explain all of particle physics. It does a very good job explaining a lot, but by no means everything.


Whereas there was a "probability" that someone would eventually find the top quark 20 years ago, there's still no "probability' that any SUSY particle will EVER be found.
Unless you have definitive evidence of the non-existance of SUSY particles, the above is quite simply a baseless assertion.


We point Rhessi at the Earth and we see gamma rays from discharges in the Earth's atmosphere. We point Rhessi at the sun and see annihilation wavelengths during flares. There are at least a half dozen possible "sources' of gamma rays in just this one solar system. No doubt when we look out at *hundreds of billions of solar systems in a galaxy* we will likely observe a lot of gamma rays. If we need more of them, all we have to do is turn up the "electricity" and a known source of gamma rays in nature will produce more gamma rays.
What the hell does "all we have to do is turn up the "electricity"" mean?


The "odds" of "dark matter" being responsible for gamma rays is one in a million at best.
Yet another assertion with nothing to back it up. Unless of course you can show us a calculation of this probability.


It's never been seen on Earth in a real experiment, not one single time.
The same could be said of the top quark 20 years ago. The main reason being that our colliders weren't energetic enough. We got a higher energy collider and whadaya know. We found the top quark.
We have the successor to this coming online soon (hopefully). I wouldn't be counting my chickens if I were you.


Gamma rays occur naturally here on Earth every single day due to "electricity".
Please define "electricity".


I don't need no stinking "dark matter" to explain gamma rays of any quantity.

Even if this were the case, still doesn't explain galactic rotation curves. Oh and I'm expecting to see a full quantitative explanation of the data. SInce you are so sure you're right that must be pretty straightforward.


If we take an Occum's razor to your argument, I'm afraid it's toast.
What are you talking about? My argument was that your assertion that dark matter didn't exist because it hadn't been seen in a lab was, based on history and common sense, a ridiculous one. This has nothing whatsoever to do with Occam's razor.


There is a plentiful and abundant source of gamma rays to be found in simple "electricity".
Again, please define "electricity".

[blutoski]

So Fermi has observed "empirical" evidence of God?

Data is not evidence in its own right, but can be evidence when used to support an argument.

In terms of the argument you constructed, I will say yes. There is an enormous amount of empirical evidence that supports arguments put forward for the existence of God.

I think at this point, you've recognized that your dispute is not with the syllogisms that support scientific inquiry, but that it's concentrated on an unstated premise: that DM may exist, and a stated premise: that DM may emit gamma rays.

My impression is that you find these premises to be weak?

[Michael Mozina]

My impression is that you find these premises to be weak?

Weak in comparison to any theory related to electrical discharge theory, yes, absolutely. Nature has already demonstrated a very simple way to generate gamma rays and it puts on that show right here on Earth every single day. There are many bodies in any solar system, and the larger ones seem to have the largest discharges. Saturn's discharges are *enormous* compared to discharges here on Earth. The bigger the body, the larger the discharge.

The only variables required in any discharge theory will be related to the number and intensity of the discharge. Any theory that requires more than these variable, and has never been demonstrated to occur in nature is unjustified and unnecessary. It's that unnecessary part that kills your argument IMO. Occum's razor isn't kind to a DM source of gamma rays and there are a number of bodies inside our own solar system that experience discharges and annihilation in the atmosphere. DM theory is utterly unnecessary in terms of explaining gamma rays.

If you look at the Fermi image, the galaxy is the most obvious feature. The reason is obvious too. There are hundreds of billions of possible gamma ray sources in every sun and every planet in the galaxy. Over time we will observe a concentration of these emissions in and around the solar systems of the galaxy and distant galaxies as well. It's related to atmospheric discharges and they happen every day here on Earth.

[blutoski]

It's a push then because you have two unverified parameter (DM exists & DM emits gamma rays) as do I. So my God theory is evidently a "scientific solution" to this observation too?

'science' is often misused as a term. It literally means knowledge. (political science, christian science, computer science)

More commonly, though, people use it to represent knowledge about nature. That scientific investigation is trying to learn about natural processes. This excludes supernatural processes, so theories that incorporate 'God' are not considered scientific.





Assuming I ascribe "God" with every single parameter that you assign to 'dark matter', how exactly did you intend to falsify my God theory?

It looks falsifiable enough exactly as you originally wrote it.

If the results are negative, it's falsified.

[blutoski]

Weak in comparison to any theory related to electrical discharge theory, yes, absolutely. Nature has already demonstrated a very simple way to generate gamma rays and it puts on that show right here on Earth every single day. There are many bodies in any solar system, and the larger ones seem to have the largest discharges. Saturn's discharges are *enormous* compared to discharges here on Earth. The bigger the body, the larger the discharge.

The only variables required in any discharge theory will be related to the number and intensity of the discharge. Any theory that requires more than these variable, and has never been demonstrated to occur in nature is unjustified and unnecessary. It's that unnecessary part that kills your argument IMO. Occum's razor isn't kind to a DM source of gamma rays and there are a number of bodies inside our own solar system that experience discharges and annihilation in the atmosphere. DM theory is utterly unnecessary in terms of explaining gamma rays.

If you look at the Fermi image, the galaxy is the most obvious feature. The reason is obvious too. There are hundreds of billions of possible gamma ray sources in every sun and every planet in the galaxy. Over time we will observe a concentration of these emissions in and around the solar systems of the galaxy and distant galaxies as well. It's related to atmospheric discharges and they happen every day here on Earth.

Ah. This is the root of it. It's not so much that DM->gamma rays is obviously wrong, it's just that it competes with your pet theory.

My impression is that you feel they will not be able to resolve between these two theories with the existing programme and apparatus - that positive results that should vindicate you will be incorrectly interpreted as support for another theory.

[Michael Mozina]

It certainly doesn't explain all of particle physics. It does a very good job explaining a lot, but by no means everything.

I intentionally used the term "key" by the way. What exactly does it not explain that you feel is somehow critically important to particle physics theory?

Unless you have definitive evidence of the non-existance of SUSY particles, the above is quite simply a baseless assertion.

The assertion that they exist is baseless. The assertion they emit gamma rays is a baseless assertion. No such particle has ever been confirmed to exist in any empirical experiment done to date. I have no evidence any such particle will ever be found, and no evidence that any such particle would emit gamma rays, positrons or anything else. I have no evidence they exist at all, so pointing at the sky and claiming "dark matter did it" is a baseless assertion.

At least the statement "electrical discharges did it" has empirical support here on Earth and throughout our solar system.

What the hell does "all we have to do is turn up the "electricity"" mean?

If we need more gamma rays, we need more discharge to occur. If we need larger discharges all we have to do is crank up the current flow. I think I'll go grab a beer before I finish the rest of your post. It's getting to be late afternoon here on a Friday and there are some perks to being self employed. :) BRB.....

[Michael Mozina]

'science' is often misused as a term. It literally means knowledge. (political science, christian science, computer science)

More commonly, though, people use it to represent knowledge about nature. That scientific investigation is trying to learn about natural processes. This excludes supernatural processes, so theories that incorporate 'God' are not considered scientific.

How very "unscientific" of you IMO. :)

How do you know that God is not "nature" itself? In other words, how do you know God isn't everything that we observe in the night sky and more than we can ever hope to see from this little mud ball in space? How do you know that the universe itself is not "aware"?

It looks falsifiable enough exactly as you originally wrote it.
If the results are negative, it's falsified.

Ok. What we're essentially suggesting is that any standard Lambda-CDM theory can instantly be converted to Lambda-God theory simply by renaming some of the variables. How then is Lambda-"Fill in the variable name" theory not a "religion" and what exactly makes it "scientific"?

[Michael Mozina]

Ah. This is the root of it. It's not so much that DM->gamma rays is obviously wrong, it's just that it competes with your pet theory.

No, it's that electrical discharges are already a known and demonstrated source of gamma rays on Earth, and gamma rays around larger bodies in the solar system. What do we need dark energy for?

I'm not sure I quite understand your last paragraph. Maybe it's the beer? :)

[Tubbythin]

I intentionally used the term "key" by the way.
So you did. Feel free to pretend it was in my original response.


What exactly does it not explain that you feel is somehow critically important to particle physics theory?
Well it doesn't unify the three non-gravitational forces. It doesn't really explain the neutrino masses. And it does contain quite a few free parameters.


The assertion that they exist is baseless.
There are good theoretical reasons for thinking they might exist. Due to symmetry properties much like the existence of the top quark was inferred from symmetry principles. They could also help explain at least one of the shortcomings of the SM I mentioned above. And at least one I didn't mention. And that's before we even mention DM.


The assertion they emit gamma rays is a baseless assertion. No such particle has ever been confirmed to exist in any empirical experiment done to date.
Much like the top quark twenty years ago. The top quark didn't just suddenly come into existence for the first time when it was found at Fermilab though.


I have no evidence any such particle will ever be found, and no evidence that any such particle would emit gamma rays, positrons or anything else.
Maybe you should actually read up about what you're arguing against then.

I have no evidence they exist at all, so pointing at the sky and claiming "dark matter did it" is a baseless assertion.
I personally had no evidence for the existence of the top quark in the early 1990's. What's your point?


At least the statement "electrical discharges did it" has empirical support here on Earth and throughout our solar system.
And you think there is no evidence of gamma rays from high-energy particle interactions?


If we need more gamma rays, we need more discharge to occur. If we need larger discharges all we have to do is crank up the current flow.
Where? Either you have a quantitative model to defend or you have nothing. Which is it?

[DeiRenDopa]

No, it's that electrical discharges are already a known and demonstrated source of gamma rays on Earth, and gamma rays around larger bodies in the solar system. What do we need dark energy for?

[...]
Indeed.

But do the numbers add up?

Or is it - once again - a case of "who the **** cares about *********** numbers! :mad:" ?

In short, have you not, for the umpteenth time, demonstrated that the MM worldview is blind to quantitative analyses? Or, to be blunt, that your approach is antithetical to science?

[Michael Mozina]

Well it doesn't unify the three non-gravitational forces. It doesn't really explain the neutrino masses. And it does contain quite a few free parameters.

Fair enough. I think most folks figure that will come about via QM sooner or later. How does SUSY theory solve any of those issues?

I'm going to skip the irrelevant stuff if you don't mind.

I personally had no evidence for the existence of the top quark in the early 1990's. What's your point?

My point is that even in the early 1990's there was a 'likelihood' that it would be found. There is no such likelihood as it relates to SUSY theory. I guess I may not understand what specific issue you believe SUSY theory will solve and I probably need to hear that answer before I can continue.

And you think there is no evidence of gamma rays from high-energy particle interactions?

Sure. I don't have any problem with you attributing gamma rays to anything that can be empirically demonstrated.

Where? Either you have a quantitative model to defend or you have nothing. Which is it?

http://www.sciencemag.org/cgi/content/summary/307/5712/1054

If you mean have I personally sat down to explain the Fermi data with electrical discharges and known solar activities, no, I have not done that. I haven't even seen a full solar cycle in Fermi data yet, so how would I know what is "normal" output for our own sun?

[Michael Mozina]

Please define "electricity".

Inside a mostly plasma universe is I would describe it as "current flow". Moving ions can contain a charge as well as electrons, and protons.

Even if this were the case, still doesn't explain galactic rotation curves. Oh and I'm expecting to see a full quantitative explanation of the data. SInce you are so sure you're right that must be pretty straightforward.

I'm willing to accept that there is "missing mass" in a galaxy that our current mass estimates cannot account for based on the lensing data I have seen. I therefore prefer a "missing mass" theory over a MOND theory for instance. That does not mean that any of the "missing mass" in located in any form of exotic materials that do not show up in particle physics experiments and/or the periodic table.

What are you talking about? My argument was that your assertion that dark matter didn't exist because it hadn't been seen in a lab was, based on history and common sense, a ridiculous one. This has nothing whatsoever to do with Occam's razor.

I'm saying that there is already a known and demonstrated "natural" way to generate gamma rays. There is no need for DM. It's not going to survive an Occum's razor argument.

[Michael Mozina]

Indeed.

But do the numbers add up?

Or is it - once again - a case of "who the f*** cares about f***ing numbers! :mad:" ?

In short, have you not, for the umpteenth time, demonstrated that the MM worldview is blind to quantitative analyses? Or, to be blunt, that your approach is antithetical to science?

I guess if I *had* to choose between the two, I'd rather be blind to the quantitative analysis than to be blind to the qualitative analysis like you. :)

How exactly would you suggest that we go about computing a number of photons counts to expect from a sun and from the planets when we haven't a full solar cycle to work with?

http://www.space.com/scienceastronomy/080515-galactic-dust.html
http://cmarchesin.blogspot.com/2009/08/galaxies-demand-stellar-recount.html

Have these more recent discoveries even been factored into current galaxy estimates in terms of the number of stars there are in a given galaxy, including our own? How many gamma ray emitting planets shall we assume for every star in your opinion?

I know how much you love to simply ignore the qualification side of empirical physics and all that matter to you is the math, but don't you get tired of just pulling these numbers out of thin air and then seeing them be demonstrated to be wrong over and over again?

From a 'qualitative" side of science, you haven't a leg to stand on and your math is just fancy window dressing. It's still just mathematical lipstick on a metaphysical pig.

[Tubbythin]

Fair enough. I think most folks figure that will come about via QM sooner or later.
Such as supersymmetry.

How does SUSY theory solve any of those issues?
It allows the coupling constants of the three forces to meet at a single distance/energy scale which would allow for a "natural" GUT. I guess this would also lead to less free parameters although I'm a little rusty here.


My point is that even in the early 1990's there was a 'likelihood' that it would be found. There is no such likelihood as it relates to SUSY theory.
Best tell all those people at CERN who are wasting there time then. They certainly seem to believe its a distinct possibility.


I guess I may not understand what specific issue you believe SUSY theory will solve and I probably need to hear that answer before I can continue.

Google it. I'm sure you can find better sources than me.


Sure. I don't have any problem with you attributing gamma rays to anything that can be empirically demonstrated.
But a number of these things were empirically demonstrated from measuring the gamma-rays in the first place! If you rule out the empirical evidence that something exists based on the fact that its never been shown to exist before then you're never going to discover anything new at all.


http://www.sciencemag.org/cgi/content/summary/307/5712/1054
I can't read the paper. But based on the abstract, the phenomena described are too low in energy by a factor of at least 50 compared to the data in the FGST paper. So I'm not sure what the relevance is.


If you mean have I personally sat down to explain the Fermi data with electrical discharges and known solar activities, no, I have not done that. I haven't even seen a full solar cycle in Fermi data yet, so how would I know what is "normal" output for our own sun?
I'm not sure why you need a full solar cycle.

[Tubbythin]

Inside a mostly plasma universe is I would describe it as "current flow". Moving ions can contain a charge as well as electrons, and protons.
So what did you mean by
If we need more of them, all we have to do is turn up the "electricity" and a known source of gamma rays in nature will produce more gamma rays.
?


I'm willing to accept that there is "missing mass" in a galaxy that our current mass estimates cannot account for based on the lensing data I have seen. I therefore prefer a "missing mass" theory over a MOND theory for instance. That does not mean that any of the "missing mass" in located in any form of exotic materials that do not show up in particle physics experiments and/or the periodic table.
Actually it does, precisely because of the successes of the Standard Model. It cannot be explained by anything that interacts electromagnetically. That leaves neutrinos. But neutrinos are too light.


I'm saying that there is already a known and demonstrated "natural" way to generate gamma rays. There is no need for DM. It's not going to survive an Occum's razor argument.
a) This was not my argument (not at the time anyway).
b) There is from the galactic distribution curves etcetera.
We have no simple explanation of the source of the gamma rays. You are unable to provide a quantitative explanation. And neither has anybody else.
Therefore dark mater is a possibility. But even if its something more mundane there's still those galactic rotation curves, those cluster rotation curves and various other things supporting the existence of DM.

[DeiRenDopa]

I guess if I *had* to choose between the two, I'd rather be blind to the quantitative analysis than to be blind to the qualitative analysis like you. :)

How exactly would you suggest that we go about computing a number of photons counts to expect from a sun and from the planets when we haven't a full solar cycle to work with?

http://www.space.com/scienceastronomy/080515-galactic-dust.html
http://cmarchesin.blogspot.com/2009/08/galaxies-demand-stellar-recount.html

Have these more recent discoveries even been factored into current galaxy estimates in terms of the number of stars there are in a given galaxy, including our own? How many gamma ray emitting planets shall we assume for every star in your opinion?

I know how much you love to simply ignore the qualification side of empirical physics and all that matter to you is the math, but don't you get tired of just pulling these numbers out of thin air and then seeing them be demonstrated to be wrong over and over again?

From a 'qualitative" side of science, you haven't a leg to stand on and your math is just fancy window dressing. It's still just mathematical lipstick on a metaphysical pig.
So tell me, MM, what was the proper - i.e. kosher according to the MM worldview of science - thing to have done wrt the original dark matter (i.e. Neptune)?

And would you have railed vociferously against all those who sought to test GR (the solution to the second lot of solar system dark matter, a.k.a. the anomalous advance of the perihelion of Mercury), because it had not been demonstrated in any earthly labs?

Wrt your quantitative questions: pick a number (or ten), MM, as long as it is consistent with all relevant observations, turn the handle, and produce for us an upper estimate of the gamma ray SED you'd expect Fermi to observe, from all the kings horses (the MW stars) and all the kings men (the MW planets).

And when you've done that, compare it to what Fermi has actually observed, write up your work, and submit the paper to ApJ (or similar).

Wait! You don't even need to do that ... the back of an old envelope would do, wouldn't it?

[Reality Check]

And since ordinary suns release these same exact gamma rays on a regular basis you have absolutely nothing to support your claim.

Stars do emit a small amount of gamma rays.
I do not make the claim that there is a Fermi haze. The paper does.
You make the claim that this invalidates the paper. Now give your evidence that it does.


So what? Based on what evidence? Point at the sky claims?

Based on actually reading their paper.


The fact that these authors make exactly the same mistake you're making doesn't justify the error.

What error? Citation please. Or a fully worked example of the gamma sources that they missed.
Their conclusion was that new physics (e.g. the decay or annihilation of dark matter) or new astrophysics is the mechanism producing the excess gamma rays.

So your original logic was wrong and there is no fallacy.


So suns are a perfectly "natural" source for such emissions and we have no need for anything exotic.

They are not a perfectly "natural" source for such emissions until you give evidence for that they are.


Uh, yes, but what does that have to do with anything? You asked for evidence that Fermi could see a sun. I provided that evidence. Gamma rays are definitely coming from our sun and likely all suns in the galaxy. It's hardly a surprise then when we can observe the galaxy in gamma rays in a Fermi image.
I asked for evidence that the Ferrm data sees gamma radiation from stars - a plural.


It is clear that stars emit gamma rays. We detect them from the Sun. The questions is:

Is the amount of gamma rays emitted by the stars in the galaxy large enough to be detected by Fermi?
My guess is no.

If it was then the NASA movie would show the stars moving, especially the nearer stars.
People who know about this stuff (unlike you and me, MM!), take account of strongly emitting objects like X-ray binaries, pulsars, etc.
They then confirm that there is no contribution from other point sources to the spectrum of the Fermi haze .
Point sources in the paper (http://arxiv.org/abs/0910.4583) :
In this fit, we mask out all of the Fermi 3-month point source catalog as well as the LMC, SMC,Orion-Barnard’s Loop, and NGC 5090.

Appendex A is all about the effects of unresolved point sources! This includes normal stars (AFAIK).
It concludes

As Fig. 13 shows, at low energies we find values of R consistent with a significant point source component (although the point source fraction cannot be precisely determined without knowing the luminosity function). Above 10 GeV, however, the value of R is consistent with entirely diffuse emission, and at 95% confidence, the fraction of emission from unresolved point sources cannot exceed ~ 5% and remain consistent with the measured value of R. Therefore,even for these conservative assumptions, the hard spectral shape of the Fermi haze cannot be caused by point source contamination.

[Beerina]

I don't know if anyone's mentioned this, yet, but the galaxy's star rotation indicates the existence of matter well in excess of that of adding up the mass of the stars.

Galaxies look like a bunch of stars swirling down a drain. In this case, the supposition is they're all in orbit, more or less, about the center of the galaxy, which has the vast bulk of mass, and thus gravity.

Except that when scientists measured how fast stars were going around the center of the galaxy, it was much closer to a solid disc rotating than a bunch of swirling stars.

The only way that can happen is if there's a lot more mass way outside the core of the galaxy so there's a counterpull of gravity that counteracts a lot of the swirliness. There isn't that much swirliness if you're being pulled from both sides almost equally.

Now stars are huge, and a hundred billion are a massive amount of mass, but it's no way near enough to account for that observed behavior.

SO, there must be a lot more mass, i.e. matter somewhere, but we can't see it, so "dark matter" it is. The rest so far is trying to derive characteristics of it -- doesn't interact with observable frequencies, etc.

Any ideas? Have fun! :) But it's not just pulled out of their ass. And other theories besides matter are being considered, I'm sure, from measurement errors to new forces that act on massive scales and so on.

[Michael Mozina]

I don't know if anyone's mentioned this, yet, but the galaxy's star rotation indicates the existence of matter well in excess of that of adding up the mass of the stars.

Galaxies look like a bunch of stars swirling down a drain. In this case, the supposition is they're all in orbit, more or less, about the center of the galaxy, which has the vast bulk of mass, and thus gravity.

Except that when scientists measured how fast stars were going around the center of the galaxy, it was much closer to a solid disc rotating than a bunch of swirling stars.

The only way that can happen is if there's a lot more mass way outside the core of the galaxy so there's a counterpull of gravity that counteracts a lot of the swirliness. There isn't that much swirliness if you're being pulled from both sides almost equally.

Now stars are huge, and a hundred billion are a massive amount of mass, but it's no way near enough to account for that observed behavior.

SO, there must be a lot more mass, i.e. matter somewhere, but we can't see it, so "dark matter" it is. The rest so far is trying to derive characteristics of it -- doesn't interact with observable frequencies, etc.

Any ideas? Have fun! :) But it's not just pulled out of their ass. And other theories besides matter are being considered, I'm sure, from measurement errors to new forces that act on massive scales and so on.

As I have explained in the past, due to the lensing data I've seen, the concept of "unidentified mass" or 'missing mass' is more appealing to me than say MOND theory.

IMO that simply demonstrates we grossly underestimate the amount of mass in a galaxy. Those links I cited for DRD demonstrate the recent discoveries suggest we have grossly underestimated the amount of dust in the universe as well as the number of smaller stars in a galaxy. Have these more recent discoveries even had a chance to be factored into our galaxy mass estimates?

The term "dark matter' as I was taught it in school was mostly though to be standard matter our technologies could not yet identify, more along the lines of MACHO orientation of 'dark matter". Today's new and improved brand is being created in an "ad hoc" manner and being assigned various "properties" that have never been demonstrated. The term "dark matter" has changed from being associated with standard material, to being mostly associated with hypothetical SUSY theory with hypothetical and metaphysical properties galore.

When we look at the Fermi images, the material doesn't seem to be concentrated in any one place around the galaxy, instead the entire galaxy seems to glow as though every star and every planet is emitting these wavelengths. That's confirmed too by the fact we can observe the sun traversing the Fermi data set quite clearly. It should hardly be surprising then that we see gamma rays from stars in a galaxy and even planets are known to emit gamma rays inside our own solar system.

There's absolutely no need for 'dark matter' to explain 'gamma rays' from a galaxy. There's no empirical link established between 'dark matter" and "gamma rays". The whole thing is "assumed", the material itself, the gamma link, the areas of concentration of DM (which don't even jive with observation), all of it. DM theory is not a "simpler" explanation for gamma rays than suns and planets. It's not supported by any observation in a controlled experiment. There is not one single instance of "dark matter" emitting gamma rays inside out solar system, so what in the world would lead me to believe it occurs "out there somewhere else"?

I'm afraid the DM source of gamma ray theory doesn't survive the first Occum's razor argument. In fact it falls apart over the simplicity factor alone. It lacks empirical support of any kind, and it's not even viable compared to the simpler and *demonstrated* sources of gamma rays.

[Tubbythin]

As I have explained in the past, due to the lensing data I've seen, the concept of "unidentified mass" or 'missing mass' is more appealing to me than say MOND theory.

IMO that simply demonstrates we grossly underestimate the amount of mass in a galaxy.
The lensing data explicitly removes the possibility that the missing mass (or rather excess mass) is in the the form of massive objects.


Those links I cited for DRD demonstrate the recent discoveries suggest we have grossly underestimated the amount of dust in the universe as well as the number of smaller stars in a galaxy. Have these more recent discoveries even had a chance to be factored into our galaxy mass estimates?
Can you show they're even in the right ballpark to make a significant difference?


The term "dark matter' as I was taught it in school was mostly though to be standard matter our technologies could not yet identify, more along the lines of MACHO orientation of 'dark matter".
Which has now been ruled out by the lensing data. Hence the transition to WIMP type objects.


Today's new and improved brand is being created in an "ad hoc" manner and being assigned various "properties" that have never been demonstrated.
Not in the slightest. For example the MSSM assigns properties (or rather a range of possibilities for the properties (mass etc)) to particles based on what we already know from the Standard Model and experiment with the added assumption of supersymmetry - something we have independent reasons for believing in. This is anything but ad hoc. In fact the properties of SUSY particles would be the same whether we'd observed DM or not.


The term "dark matter" has changed from being associated with standard material, to being mostly associated with hypothetical SUSY theory with hypothetical and metaphysical properties galore.
They don't really have any hypothetical features not observed in other particles. At least none that I can think of. And I dunno where you get the idea they are "metaphysical" properties from.


When we look at the Fermi images, the material doesn't seem to be concentrated in any one place around the galaxy, instead the entire galaxy seems to glow as though every star and every planet is emitting these wavelengths. That's confirmed too by the fact we can observe the sun traversing the Fermi data set quite clearly. It should hardly be surprising then that we see gamma rays from stars in a galaxy and even planets are known to emit gamma rays inside our own solar system.
I don't see your point.


There's absolutely no need for 'dark matter' to explain 'gamma rays' from a galaxy. There's no empirical link established between 'dark matter" and "gamma rays".
The give us a quantitative alternative.


The whole thing is "assumed", the material itself, the gamma link, the areas of concentration of DM (which don't even jive with observation), all of it.
Wrong. See above.


DM theory is not a "simpler" explanation for gamma rays than suns and planets. It's not supported by any observation in a controlled experiment.
Define "controlled experiment".


There is not one single instance of "dark matter" emitting gamma rays inside out solar system, so what in the world would lead me to believe it occurs "out there somewhere else"?
There's not a single instance of a supernova event inside our solar sytem, so what in the world would lead me to believe it occurs "out there somewhere else"?


I'm afraid the DM source of gamma ray theory doesn't survive the first Occum's razor argument. In fact it falls apart over the simplicity factor alone. It lacks empirical support of any kind, and it's not even viable compared to the simpler and *demonstrated* sources of gamma rays.
You really don't get the idea of [B]quantitative[\B] analysis do you?

[Michael Mozina]

So tell me, MM, what was the proper - i.e. kosher according to the MM worldview of science - thing to have done wrt the original dark matter (i.e. Neptune)?

You mean "unidentified mass"? When did anyone claim that this particular missing mass was able to pass through walls in a single bound? Emit gamma rays on a whim? When did anyone claim it could puke out positrons anywhere and everywhere? I'm afraid you only serve to demonstrate the obvious here. There's a lot we cannot observe directly and there is every reason to believe that we grossly blew the mass estimates as it relates to the "normal" amount of material in a galaxy. There is at least twice the "dust" we expected to find and four times as many small stars in a galaxy than we realized. You haven't even had time to factor in these changes to our understanding of a makeup of a galaxy, but you still expect me to believe you have everything so figured out that you can estimate the amount of exotic new material in distant galaxy. Come on. Your story isn't even believable. Like Neptune, I'm sure your "missing mass" is made of ordinary matter and baryonic materials.

And would you have railed vociferously against all those who sought to test GR (the solution to the second lot of solar system dark matter, a.k.a. the anomalous advance of the perihelion of Mercury), because it had not been demonstrated in any earthly labs?

No because "gravity" shows up on Earth and does its thing right here on Earth. I'm sure that gravity exists "out there" in space too. Compare and contrast that with hypothetical brands of SUSY particles with hypothetical properties galore that are entirely based on faith, starting with the claim of "longevity".

Have the "professionals" in your industry even revised their mass estimates of normal material in a galaxy based on these new findings? Yes or no? If so, which paper would you cite for us? Has the Fermi team cited these new numbers in any single paper to date?

[Michael Mozina]

The lensing data explicitly removes the possibility that the missing mass (or rather excess mass) is in the the form of massive objects.

How do you figure that? It certainly doesn't remove the possibility that ISM and IGM is "dustier" than we thought.

http://www.space.com/scienceastronomy/080515-galactic-dust.html

If it's "twice as bright" as we realized, why wouldn't that equate to a doubling of the number of stars and solar systems in a galaxy?

Even more damaging IMO:
http://cmarchesin.blogspot.com/2009/08/galaxies-demand-stellar-recount.html

Given these facts, how can you expect me to believe that we already know how much ordinary matter exists in a distant galaxy?

[Tubbythin]

How do you figure that?
The weak gravitational lensing data shows that the mass cannot be largely in the form of large objects.


It certainly doesn't remove the possibility that ISM and IGM is "dustier" than we thought.

http://www.space.com/scienceastronomy/080515-galactic-dust.html

If it's "twice as bright" as we realized, why wouldn't that equate to a doubling of the number of stars and solar systems in a galaxy?

Even more damaging IMO:
http://cmarchesin.blogspot.com/2009/08/galaxies-demand-stellar-recount.html

Given these facts, how can you expect me to believe that we already know how much ordinary matter exists in a distant galaxy?

You do know we not only know how much dark matter there is but what shape it takes right?

[DeiRenDopa]

[...]

There's a lot we cannot observe directly and there is every reason to believe that we grossly blew the mass estimates as it relates to the "normal" amount of material in a galaxy. There is at least twice the "dust" we expected to find and four times as many small stars in a galaxy than we realized.
Evidence?

Start with our own, the MW galaxy, and then either of the Magellanic Clouds, followed by any other MW satellite galaxy, followed by M31 and/or M33.

[...]

Like Neptune, I'm sure your "missing mass" is made of ordinary matter and baryonic materials.
I have no doubt whatsoever that you are, indeed, sure of this.

However, it has never been the case that the answer to a scientific question like this can be answered by asking MM what he is sure about ...

Perhaps you can put fingers to keyboard, and write a paper actually demonstrating this? And backing it up with quantitative analyses, unbiased sets of references, etc?

If you can't, what do you have, other than a personal, subjective opinion?


And would you have railed vociferously against all those who sought to test GR (the solution to the second lot of solar system dark matter, a.k.a. the anomalous advance of the perihelion of Mercury), because it had not been demonstrated in any earthly labs?
No because "gravity" shows up on Earth and does its thing right here on Earth.
Are you so grotesquely ignorant of the relevant history?

The original "dark matter" (Neptune) worked out just fine, in terms of the then prevailing theory of gravity (Newton's).

Starting around the middle of the 19th century, just the same sort of solution was sought to some new "dark matter" (i.e. the anomalous advance of the perihelion of Mercury) ... and it was even given a name (Vulcan).

Einstein's new theory of gravity did away with the need for a "dark matter" solution, but at the expense of a "dark energy" one (i.e. a theory which could not - then - be empirically tested in any lab on Earth).

An MM clone at the time (1918, say) would have railed most vociferously against this "dark energy" (i.e. an unsubstantiated theory of gravity), and insisted that astronomers lift their game in terms of searching for Vulcan.

And it was not until some four decades later - well after many of the leading astronomers of the day were dead, or had ceased any astronomical research - that GR was tested in a lab here on Earth.

Had MM been the ultimate authority on physics, at the time, no one would even have tried to test GR!

I'm sure that gravity exists "out there" in space too.
Indeed.

The only thing - wrt gravity - that you're not sure about is whether a cosmological constant is required to adequately describe it ...

... well, you also are not sure of the validity of gravitational lensing, of the ISW, of the nature of the EFE, of ...

Compare and contrast that with hypothetical brands of SUSY particles with hypothetical properties galore that are entirely based on faith, starting with the claim of "longevity".
Just like the hypothetical Neptune (as it subsequently became known) and Vulcan (which remains entirely hypothetical)?

Oh, and the "faith" basis is the same as the "faith" basis for GR, the Standard Model (of particle physics), ...



Have the "professionals" in your industry even revised their mass estimates of normal material in a galaxy based on these new findings?
I was not aware that any of these "new findings" referred to our own galaxy (the Milky Way) - can you point me to where, exactly, this reference is to be found?

Yes or no? If so, which paper would you cite for us? Has the Fermi team cited these new numbers in any single paper to date?
Why should they need to, if they have no relevance?

[Reality Check]

The term "dark matter' as I was taught it in school was mostly though to be standard matter our technologies could not yet identify, more along the lines of MACHO orientation of 'dark matter". Today's new and improved brand is being created in an "ad hoc" manner and being assigned various "properties" that have never been demonstrated. The term "dark matter" has changed from being associated with standard material, to being mostly associated with hypothetical SUSY theory with hypothetical and metaphysical properties galore.
I think I see your problem - you are stuck with the science that was taught to you in school many years ago. You have forgotten to learn, especially about the new discoveries that changed this original concept for dark matter.

Dark matter was considered to be "missing matter" from 1933 when Zwicky found that there as not enough matter measured in galactic clusters to explain the orbital motion of galaxies. This is the concept that was taught in schools for the next 40 years.

Then in 1975, came Rubin's observation that the velocity dispersions of galaxies also needed dark matter. This could also be "missing matter" but 40 years of improving observational techniques made this doubtful. Further advances in observation techniques since then finally broke the association of dark matter with "missing matter". The biggest observational straw was that fact that the leading candidate for this (MACHO's (http://en.wikipedia.org/wiki/Massive_compact_halo_object)) have been detected but not at a level high enough to explain dark matter.

The real observations that showed that dark matter could not be normal matter (i.e. "missing matter") are the colliding galactic clusters of Bullet Cluster (http://chandra.harvard.edu/photo/2006/1e0657/) and MACS J0025.4-1222 (http://hubblesite.org/newscenter/archive/releases/2008/32/) (and even Abell 520 (http://en.wikipedia.org/wiki/Abell_520)).
Here is the situation in the observations in a simplified form:

A is a big blob of gas.
B is a bib blob of gas.
Blob A hits blob A.

If the gas is all the same stuff then the result will be another blob of gas.
It is probable that some of the gas will not not collide. In that case there will be blobs of gas to each side. The size of these outlying blobs will reflect the amount of gas that did not collide.
If the gas is a mixture of two kinds of gas , one of which interacts weakly with the other, then the result will be 3 blobs since the weakly interacting gas passes through the other gas.
The size of these outlying blobs will reflect the amount of gas that did not collide plus the amount of weakly interacting gas.

We see 3 blobs.
The outlying blobs contain most of the matter.
Thus the gas is made of two kinds of gas, one of which interacts weakly with the other.
You may want to read Starts With a Bang's clear description of Dark Matter in his blog entries.

Dark Matter Part I: How Much Matter is There? (http://scienceblogs.com/startswithabang/2009/09/dark_matter_part_i_how_much_ma.php)
Dark Matter Part II: How much Normal Matter is there? (http://scienceblogs.com/startswithabang/2009/09/dark_matter_part_ii_how_much_n.php)
Dark Matter Part III: Dark Matter or Modified Gravity? (http://scienceblogs.com/startswithabang/2009/09/dark_matter_part_iii_dark_matt.php)
Dark Matter Part 3.5: When Clusters Collide! (http://scienceblogs.com/startswithabang/2009/09/dark_matter_part_35_when_clust.php)
Dear MOND: Time for a New Song! (Dark Matter pt. IV) (http://scienceblogs.com/startswithabang/2009/10/dear_mond_time_for_a_new_song.php)
He also mentions the fact that astronomers measure the mass distribution of galactic clusters and see that the majority of matter is not visible. Have a look at The Camera that Changed the Universe: Part 4 (http://scienceblogs.com/startswithabang/2009/05/the_camera_that_changed_the_u4.php)
What can you learn from this? Well, other than all sorts of things about the lensed galaxies, you can learn about dark matter! You see, gravitational lensing only cares about mass, and so we can figure out where -- in a cluster like this -- the mass is distributed. The results are breathtaking.
http://scienceblogs.com/startswithabang/upload/2009/05/the_camera_that_changed_the_u4/mass_recon0024_500.jpg
What this shows you is that yes, there are spikes where the individual galaxies are. But the cluster is dominated by this giant spherically-distributed mass that's present everywhere, both where there are galaxies and where there aren't. And that has got to be dark matter.

[sol invictus]

There's a very close analogy to the topic of this thread, one that demonstrates the absurdity of MM's position (and the danger it would pose to progress were anyone else to subscribe to it). The analogy is the solar neutrino problem.

Must as Fermi (and other experiments) have detected an unexplained excess of positrons and photons produced by electron-positron annihilation, neutrino detectors starting in the 60's found a strange deficit in the flux of solar neutrinos (specifically, they detected about 1/2 the number expected based on the standard solar model).

Then as now, there were a few possibilities:

1) the experimental results were wrong

2) the standard solar model was wrong, and once that mistake was corrected the measured flux would agree with theory

3) something really new was responsible

Possibility 1) was largely eliminated by more experiments (which found consistent results). Possibility 2) was looked at very closely over many years, but no one could find a problem in the solar model that explained the deficit.

At the same time theorists proposed a far more radical idea fitting into 3): that neutrinos have mass, and moreover that their mass eigenstates do not line up with their flavor eigenstates, which means one type of neutrino can spontaneously turn into another type (thereby avoiding detection in some types of detectors and reducing the measured flux).

Of course that radical theory is now know for certain to be correct. In this case the final confirmation was provided by "lab" experiments (you produce neutrinos at a nuclear reactor, beam them a long distance at an angle that takes them through the crust of the earth, detect them far away when they emerge, and note that some have oscillated into others). If these theories of dark matter being responsible for the excess gamma rays and positrons are correct, it's possible that they will eventually be established in accelerators. But that possibility is irrelevant to whether or not the theories are correct now - they either are or are not, whether or not we can tell. MM's insane criteria - which is that we should not look for anything that hasn't already been found - would preclude any such search, and so we would never know. In the case of solar neutrinos, since there was no evidence (apart from the observed deficit) that neutrinos had mass, MM's criterion would have prevented any experiment from being built to test it, or for that matter any theorists to come up with the idea in the first place. All of that is literally antithetical to science.

I think a good term for the position MM advocates: "antiscience".

[Tubbythin]

There's a very close analogy to the topic of this thread, one that demonstrates the absurdity of MM's position (and the danger it would pose to progress were anyone else to subscribe to it). The analogy is the solar neutrino problem.


Sadly the analogy doesn't work on anyone "sceptical" of neutrino oscillations.

[sol invictus]

Sadly the analogy doesn't work on anyone "sceptical" of neutrino oscillations.

Neutrino oscillations have been confirmed in lab experiments.

But anyway, I'm not trying to convince MM - that's useless. I'm assuming other people might read this thread, and neutrino oscillations are a very good example of the kind of fundamental particle physics that can be learned from astrophysical observations. The correction to the standard model of particle physics that resulted from that was the first one in something like 30 years.

[DeiRenDopa]

[...]

http://www.space.com/scienceastronomy/080515-galactic-dust.html
http://cmarchesin.blogspot.com/2009/08/galaxies-demand-stellar-recount.html

Have these more recent discoveries even been factored into current galaxy estimates in terms of the number of stars there are in a given galaxy, including our own? How many gamma ray emitting planets shall we assume for every star in your opinion?

[...]
Can you please confirm that The energy output of the Universe from 0.1 micron to 1000 micron (http://arxiv.org/abs/0803.4164) and Evidence for a Non-Uniform Initial Mass Function in the Local Universe (http://arxiv.org/abs/0902.0384) are the papers you are referring to?

[Tubbythin]

Neutrino oscillations have been confirmed in lab experiments.
I know that (just so we're clear).

[Michael Mozina]

Neutrino oscillations have been confirmed in lab experiments.

That's exactly why your analogy (and DRD's analogy fail).

Unlike the hypothetical "dark matter" particle you're claiming is responsible for gamma rays in space, neutrinos have a known source. They show up in labs. We can create "transmitters' and "detectors" and real equipment to measure them. We can see how they interact with matter.

Where does your mythical dark matter particle thingy come come? Where can I get some of this stuff to play with in lab? How do I detect here here in a lab? Unlike gravity and neutrinos that show up here on Earth, why doesn't this stuff do anything to anything here on Earth? Why doesn't it emit gamma rays here too? How do I build a "transmitter" of "dark matter"? How do I verify this new particle has the various properties you claim? For instance, how do I know it experiences "longevity" and doesn't decay into something else we already observe in less than a millisecond? How can I verify it emits gamma rays in an empirical test?

[DeiRenDopa]

That's exactly why your analogy (and DRD's analogy fail).

Unlike the hypothetical "dark matter" particle you're claiming is responsible for gamma rays in space, neutrinos have a known source. They show up in labs. We can create "transmitters' and "detectors" and real equipment to measure them. We can see how they interact with matter.

Where does your mythical dark matter particle thingy come come? Where can I get some of this stuff to play with in lab? How do I detect here here in a lab? Unlike gravity and neutrinos that show up here on Earth, why doesn't this stuff do anything to anything here on Earth? Why doesn't it emit gamma rays here too? How do I build a "transmitter" of "dark matter"? How do I verify this new particle has the various properties you claim? For instance, how do I know it experiences "longevity" and doesn't decay into something else we already observe in less than a millisecond? How can I verify it emits gamma rays in an empirical test?
You keep missing the point, and denying history.

Helium was detected "in the lab" after it was discovered in the Sun.

Nebulium (the hypothesised source of the 500.7 nm (etc) emission lines) was determined to be not a new element well after it was first observed (and [OIII] lines have never been observed "in the lab").

Neutrino oscillations were observed "in the lab" after they were confirmed as a consistent explanation of the solar neutrino problem.

The inverse square nature of (Newtonian) gravitation was confirmed "in the lab" well after the theory was first published.

GR was not tested "in the lab" until well after it was confirmed as a consistent explanation for several sets of astronomical observations.

The neutrino was not observed "in the lab" until after it was confirmed as a consistent explanation for several sets of experimental results.

And so on.

Yet, according to the MM worldview, none of the explanations were legitimate at the time they were first proposed; furthermore, according to this worldview, no "in the lab" tests should ever have been conducted, because there were - at the time, and still today - qualitative explanations that an MM clone could plausibly claim might account for the relevant observations. In this MM worldview, the failure of any such alternative explanation to come even close to being able to account for all relevant results - quantitatively - is utterly irrelevant.

To quote from si's recent post: "I think a good term for the position MM advocates: "antiscience"."

[sol invictus]

That's exactly why your analogy (and DRD's analogy fail).

Unlike the hypothetical "dark matter" particle you're claiming is responsible for gamma rays in space, neutrinos have a known source.

As DRD points out, your own analogy demolishes your position. Neutrinos were posited to explain yet another mysterious deficit (missing energy and momentum in certain radioactive decays, in that case). There was zero direct evidence for their existence, they had never been detected, and their properties were hypothetical and almost completely unknown. By your logic, they should never have been proposed, never investigated, they weren't science.

Where does your mythical dark matter particle thingy come come? Where can I get some of this stuff to play with in lab? How do I detect here here in a lab? Unlike gravity and neutrinos that show up here on Earth, why doesn't this stuff do anything to anything here on Earth? Why doesn't it emit gamma rays here too? How do I build a "transmitter" of "dark matter"? How do I verify this new particle has the various properties you claim?

Every single one of those objections applied to neutrinos when they were first proposed.

For instance, how do I know it experiences "longevity" and doesn't decay into something else we already observe in less than a millisecond?

Because if it did, it wouldn't be dark matter. One of the things we know about dark matter is that it's very stable (has a long lifetime), otherwise it would have decayed.

How can I verify it emits gamma rays in an empirical test?

For now, by looking in the right places. Eventually, perhaps by creating it in an accelerator.

[Reality Check]

Where can I get some of this stuff to play with in lab? How do I detect here here in a lab? Unlike gravity and neutrinos that show up here on Earth, why doesn't this stuff do anything to anything here on Earth? Why doesn't it emit gamma rays here too? How do I build a "transmitter" of "dark matter"? How do I verify this new particle has the various properties you claim? For instance, how do I know it experiences "longevity" and doesn't decay into something else we already observe in less than a millisecond? How can I verify it emits gamma rays in an empirical test?
You are really out of date with your scientific knowlege. You seem to be stuck in your school boy days (some sort of second childhood?)

You can get dark matter anywhere you like (just like neutrinos). They are all around you.
You can detect them just like you can detect them neutrinos. Build a detector sensitive enough to detect them.
Dark matter may do stuff to things here on Earth (see the DAMA/NaI (http://forums.randi.org/wiki/DAMA/NaI), DAMA/LIBRA (http://forums.randi.org/wiki/DAMA/LIBRA) experiments).
If dark matter emits gamma rays then it emits it here too. The problem is detecting it, e.g. separating it from the much bigger source of gamma rays from natural radition (including the Sun). That is scientists are looking at the much larger density of dark matter at the center of the galaxy.
To build a transmitter, firstly build a machine that duplicates the energies of the early universe to produce dark matter particles. Then build a device to channel the dark matter into a beam (black holes may be needed).

[Michael Mozina]

As DRD points out, your own analogy demolishes your position.

No, your own two analogies demolish your position, not mine. Whereas neutrinos and gravity show up in lab, your mythical "dark matter" dohickies do not.

Neutrinos were posited to explain yet another mysterious deficit (missing energy and momentum in certain radioactive decays, in that case).

Ya, *CONTROLLED* experiments demonstrated that A) either a law of physics was being violated, or B) there was in fact a new particle required to explain that loss of energy. Notice that not a single "controlled" experiment ever required a SUSY particle to explain it and no laws of physics are violated by an absence of SUSY particles. Already your neutrino analogy shows the weakness of your own argument, and DRD's argument too. Both gravity and neutrinos have a known source and we can replicate them in a lab. You can't even be sure SUSY particles exist, let alone replicate any of the properties you keep assigning to them.

There was zero direct evidence for their existence, they had never been detected, and their properties were hypothetical and almost completely unknown. By your logic, they should never have been proposed, never investigated, they weren't science.

Boloney. Empirical controlled experiments made it clear that either a law of physics was violated (highly unlikely) or a new particle was in order (more likely). There as a *SOURCE* identified and a METHOD of observing their direct influences on controlled experiments. You can't identify a source of SUSY particles. You don't even know if they exist at all!

Gravity isn't shy around the lab so DRD's analogy is also meaningless. You're both comparing metaphysical apples to empirical oranges.

Because if it did, it wouldn't be dark matter. One of the things we know about dark matter is that it's very stable (has a long lifetime), otherwise it would have decayed.

Correction: One of the things you *NEED* from you ad hoc gap filler is longevity because without it, your theory is toast. You therefore "made up" a "necessary property" for your mythical gap filler, in this case longevity. It was a property you created based on *NEED* not upon "observation" in a lab.

For now, by looking in the right places. Eventually, perhaps by creating it in an accelerator.

Even if we do ever find a SUSY particle in a collider experiment, how do you know it's going to last even a full millisecond before reverting into something we already know about? Pure faith? Ad hoc need? What?

[Michael Mozina]

You keep missing the point, and denying history.

No, that's your game, not mine. You're mixing and matching things at will and ignoring the key differences.

Helium was detected "in the lab" after it was discovered in the Sun.

No, a wavelength of light that could not (yet) be identified was observed coming from the sun. Helium was discovered to emit that wavelength in a lab, in controlled conditions. Nothing about the idea was 'untestable' and "unfalsifiable" like your non baryonic DM theory.

Neutrino oscillations were observed "in the lab" after they were confirmed as a consistent explanation of the solar neutrino problem.

Again you're ignoring the implication of having a *CONTROLLED SOURCE* of neutrinos to work with. You can't even tell me where I can get some "dark matter", let alone how I might "detect" it in a controlled experiment. Holy Cow, how can you compare these things when they are clearly very different. In the case of neutrinos we can *create them*. We know where they come from. We can measure them. We can turn on and off a source of "neutrinos'. How might I turn on and off a source of "dark matter"?

The inverse square nature of (Newtonian) gravitation was confirmed "in the lab" well after the theory was first published.

And again with the ridiculous analogies. Gravity is not shy around a lab. DM never shows up in a lab. See the difference?

GR was not tested "in the lab" until well after it was confirmed as a consistent explanation for several sets of astronomical observations.

Yes ,but again "gravity" shows up here on Earth, and therefore I'm sure it occurs "out there" in space too. I have no doubt that gravity exists and has an effect on matter. Compare and contrast that to your mythical matter.

You're clearly missing the key point DRD. Gravity isn't shy around the lab. I'm therefore happy to let you point at the sky and claim "gravity did it" and I'll consider your math formulas to be "useful" in determining how well your mathematical model matches nature's expression of "gravity". Beta decays (and neutrinos) show up in a lab too and therefore they can be measured. They can be isolated in controlled experiments and mathematical models can be compared to actually results of empirical experiments. In no way can your "dark matter" be measured in an empirical experiment because you don't even know if it exists, you don't know where it comes from, you can't turn it on or off, you can't produce of gram of it for experimentation, and you're clueless as to whether it actually has any of the properties you *imagine* it has. In fact all of the "properties" that you "imagine" that it has are all related to what you "need" to prop up your otherwise dead theory. That's sounds more than a little fishy to a real skeptic.

[Michael Mozina]

I think I see your problem - you are stuck with the science that was taught to you in school many years ago. You have forgotten to learn,

Er, considering what I've been through for the past 6 years, I'm certain that is not the case.

especially about the new discoveries that changed this original concept for dark matter.

The "original concepts" of "dark matter" centered around and understanding of the limits of our current technologies and a certain amount of "humility" as it relates to our knowledge of space and distant galaxies. There we're no particular "properties" being assigned to "dark matter", other than an acknowledgment that we couldn't see it, presumably due to the limits of our technology.

Today's "new and improved" brand of metaphysical dark matter has all sorts of "superproperties". It's no longer "dark" because of a limit of our technology, it's "dark" because it does not interact with the EM spectrum. It's like superman only better. It can pass through walls. It can emit gamma rays with a single thought. It does what no other type of matter can do, and makes up the majority of the universe according to you guys/gals. We evidently "know" all this because our technology is presumably no longer limited, we have everything all figured out in terms of number of stars in a galaxy, amount of dust in the universe, the "superiority" of our infallible mass estimates of galaxies, etc.

That's all just hogwash. Our technologies are still very limited. We can't see individual stars in distant galaxies we "estimate" them based on a whole series of "assumptions", assumptions that are evidently pretty useless at actually guestimating the amount of mass in a galaxy. Instead of just noting that our mass estimation techniques are critically flawed, we now just *assume we're right* and we "make up" properties in a purely ad hoc manner and make up excuses about how "dark matter" did it.

Dark matter was considered to be "missing matter" from 1933 when Zwicky found that there as not enough matter measured in galactic clusters to explain the orbital motion of galaxies. This is the concept that was taught in schools for the next 40 years.

It was an "honest" explanation of the fact that our technologies were still quite primitive and our understanding of the universe was (is still) very limited.

Then in 1975, came Rubin's observation that the velocity dispersions of galaxies also needed dark matter. This could also be "missing matter"

Indeed. All it did is confirm that we blew our mass estimates of a galaxy and there *must* be more mass we can't account for in a galaxy. None of the *necessitates* a "new form" of mass. Any old mass will do.

but 40 years of improving observational techniques made this doubtful.

How so? What did you suddenly gain "perfect" technology that allowed you to count actual stars in distant galaxies that are millions if not billions of light years away?

Further advances in observation techniques since then finally broke the association of dark matter with "missing matter".

The only thing that "broke" is that your industry "broke" with empirical physics. It started 'winging it" and "making it up" as it went. No longer was it necessary to "demonstrate" any given "property" we might assign "missing matter". Now we can just "make it up" and never have to demonstrate any of it empirically. We now get to point at the sky and claim "God matter did it".

The biggest observational straw was that fact that the leading candidate for this (MACHO's (http://en.wikipedia.org/wiki/Massive_compact_halo_object)) have been detected but not at a level high enough to explain dark matter.

You're still ignoring the fact that "missing mass" isn't our disagreement. Our disagreement has do to with you *assuming* all sorts of "supernatural" properties about the nature of this "unidentified mass". It's like you see something flying around in the sky that you personally can't identify so you immediately *ASSUME* that it's from a whole different planet!

The real observations that showed that dark matter could not be normal matter (i.e. "missing matter") are the colliding galactic clusters of Bullet Cluster (http://chandra.harvard.edu/photo/2006/1e0657/) and MACS J0025.4-1222 (http://hubblesite.org/newscenter/archive/releases/2008/32/) (and even Abell 520 (http://en.wikipedia.org/wiki/Abell_520)).

Explain *EXACTLY* (and I mean exactly) how any of that stuff demonstrates that it cannot be ordinary matter that our technologies simply cannot account for?

Here is the situation in the observations in a simplified form:
[LIST=1]
A is a big blob of gas.
B is a bib blob of gas.
Blob A hits blob A.

Your analogy is pitifully oversimplified. Galaxies are composed of solar systems that are separated by light years. The odds of any of them actually slamming into one another during a "galaxy collision" are astronomically low. It's far more probable that much of the gas in the ISM would 'interact" and have some effect on the movement of the dust in the other galaxy's ISM, but the majority of the matter in a given solar system is going to go right on through the "collision" process relatively unscathed. All that data demonstrates is that most of your "missing mass" is evidently located in the stars and solar systems and point like masses rather than the dust particles in the ISM.

He also mentions the fact that astronomers measure the mass distribution of galactic clusters and see that the majority of matter is not visible.

Ya, so? Is that a limit of our technology perhaps, or do you really believe that we have the capability of "seeing" everything there is to see in a distant galaxy that is millions or billions of light years away?

[Michael Mozina]

Evidence?

From the article and paper I cited earlier:

Astronomers have known about interstellar dust for a while, but they haven't been able to quantify just how much light it blocks. Now a team of researchers has studied a catalogue of galaxies and found that dust shields roughly 50 percent of their light.

"I was shocked by the sheer scale of the effect," said Simon Driver, an astronomer from the University of St. Andrews in Scotland who led the study. "Most people just kind of said, 'We suspect dust is a minor problem.' I spent much of my career working on deep images from Hubble and I've always ignored dust almost entirely."

The result will likely cause many astronomers to revise their calculations of the intrinsic brightness of many celestial objects, Driver said. Until now, many astronomers thought stars and galaxies were really about 10 percent brighter in optical light than they appeared because of dust. If the new findings are true, it turns out that objects in the sky are about twice as bright than they appear.

"This is a strong, clear-cut result," Driver told SPACE.com. "We've really got to take dust seriously and we've got to make large adjustments to our magnitude calculations." (A magnitude scale is used to define brightness of celestial objects.)

Why should they need to, if they have no relevance?

So you're telling me that it is absolutely irrelevant that we've been underestimating the amount of brightness by such a significant percentage? It has *NO* affect whatsoever on our mass estimation of a galaxy?

[Tubbythin]

No, your own two analogies demolish your position, not mine. Whereas neutrinos and gravity show up in lab, your mythical "dark matter" dohickies do not.
But they didn't at the time they were proposed. What is it that you don't understand about this really really basic argument?


Ya, *CONTROLLED* experiments demonstrated that A) either a law of physics was being violated, or B) there was in fact a new particle required to explain that loss of energy.

Controlled experiments demonstrate the need for matter that only interacts weakly. This could be SUSY particles. On the other hand, it may not be.


Notice that not a single "controlled" experiment ever required a SUSY particle to explain it
That probably depends on whether you think we should be looking for GUTs. There's also the small matter of the hierarchy problem which you might like to stick in your favourite search engine.


and no laws of physics are violated by an absence of SUSY particles. Already your neutrino analogy shows the weakness of your own argument, and DRD's argument too. Both gravity and neutrinos have a known source and we can replicate them in a lab. You can't even be sure SUSY particles exist, let alone replicate any of the properties you keep assigning to them.


Boloney. Empirical controlled experiments made it clear that either a law of physics was violated (highly unlikely) or a new particle was in order (more likely).
Exactly the same with dark matter. Either our law of gravity is being violated or a new particle is required. You're not helping your argument here.


There as a *SOURCE* identified and a METHOD of observing their direct influences on controlled experiments. You can't identify a source of SUSY particles. You don't even know if they exist at all!
Uh-huh. You really don't this science malarkey do you. You're arguing against the existence of something because we don't know that it exists for definite. If we always did this we'd have no science at all.


Gravity isn't shy around the lab so DRD's analogy is also meaningless.
The properties of gravity that were noticed by Newton at the time, like the -2 dependance were completely impossible to measure at the time in a lab. It took centuries for this to be rectified.


You're both comparing metaphysical apples to empirical oranges.

Its not metaphysics at all.


Correction: One of the things you *NEED* from you ad hoc gap filler is longevity because without it, your theory is toast. You therefore "made up" a "necessary property" for your mythical gap filler, in this case longevity.
Nope completely wrong. The lightest particle in the Minimal Supersymmetric Standard Model (for instance) is stable. That is, the simplest possible extension that we can make to the Standard Model to include supersymmetry gives a stable supersymmetric partner. This is in no way made up. Its a consequence that is dependent only on our knowledge of the SM, QM and the assumption that the Universe is supersymmetric.


It was a property you created based on *NEED* not upon "observation" in a lab.
Nope. Completely wrong. Why do you continue to argue against something you have no idea about in such an agressive manner?


Even if we do ever find a SUSY particle in a collider experiment, how do you know it's going to last even a full millisecond before reverting into something we already know about? Pure faith? Ad hoc need? What?
None of these, R-parity conservation.

[Reality Check]

So you're telling me that it is absolutely irrelevant that we've been underestimating the amount of brightness by such a significant percentage? It has *NO* affect whatsoever on our mass estimation of a galaxy?
It does have an effect - the intrinsic brightness of many celestial objects may have been underestimated. That is what the paper states.

IMO (as a non-astronomer) I would say that this has *NO* effect whatsoever on our mass estimation of a galaxy. If it did then the authors would have stated this since it is quite an important bit of astronomy.


But the mass estimation of galaxies is only one part of the detection of dark matter. Most of the normal matter in the universe turns out to be intergalactic medium, i.e. plasma.

You may want to read Starts With a Bang's clear description of dark matter in his blog entries.

Dark Matter Part I: How Much Matter is There? (http://scienceblogs.com/startswithabang/2009/09/dark_matter_part_i_how_much_ma.php)
Dark Matter Part II: How much Normal Matter is there? (http://scienceblogs.com/startswithabang/2009/09/dark_matter_part_ii_how_much_n.php)
Dark Matter Part III: Dark Matter or Modified Gravity? (http://scienceblogs.com/startswithabang/2009/09/dark_matter_part_iii_dark_matt.php)
Dark Matter Part 3.5: When Clusters Collide! (http://scienceblogs.com/startswithabang/2009/09/dark_matter_part_35_when_clust.php)
Dear MOND: Time for a New Song! (Dark Matter pt. IV) (http://scienceblogs.com/startswithabang/2009/10/dear_mond_time_for_a_new_song.php)

Although there are other ways to measure mass gravitationally, these are the main ones. They all give the same answer, too: about 25% to 30% of the total energy in the Universe is some form of gravitational mass. But what of the stars? It turns out that stars are only about 0.5% of the mass in the Universe.

Even if this article turns out to be correct and intrinsic brightness is used to calculate the mass of galaxies (I have my doubts about this) then stars become about 1% of the mass in the Universe. Dark matter then makes up the remaining 24% to 29% of gravitational mass.

[Tubbythin]

So you're telling me that it is absolutely irrelevant that we've been underestimating the amount of brightness by such a significant percentage? It has *NO* affect whatsoever on our mass estimation of a galaxy?

Well for a start, for stars of ~ 1 solar mass the mass luminosity relationship gives:

L/Lsun = (M/Msun)4

Or
M/Msun= (L/Lsun)0.25

So even if we were underestimating the luminosity of a star by a factor of 2, we'd underestimating the mass of the star by a factor of just 1.2. So no, it doesn't make a great deal of difference.

[Reality Check]

Even more damaging IMO:
http://cmarchesin.blogspot.com/2009/08/galaxies-demand-stellar-recount.html

Given these facts news articles, how can you expect me to believe that we already know how much ordinary matter exists in a distant galaxy?
Fixed your post.

I already found the paper for the article in a previous thread where you brought up this point
Evidence for a Nonuniform InitialMassFunction in the Local Universe (http://www.iop.org/EJ/abstract/0004-637X/695/1/765).

DeiRenDopa has addressed this in some posts starting with (http://forums.randi.org/showpost.php?p=5029540&postcount=349):
By comparing the paper to the PR, it is easy to see why one should always go to the primary source, especially when trying to draw inferences that are beyond what is stated.

I'll write more about this in later posts, but the techniques used to estimate total mass in galaxies are many and varied, and they give consistent answers (albeit sometimes the uncertainties are big).

Wrt this particular paper, a possible implication concerning the estimated total baryonic mass in a galaxy is: if you use a combo of estimated SFR and IMF to derive a (baryonic) mass estimate, you may have introduced a systematic error; specifically, the IMF for LSBs (low surface brightness) galaxies may be significantly different from the IMF for other galaxies (and even this is too extreme; the paper reports only estimates of the top part of the IMF, specifically O and B stars).

We do not know how much ordinary matter exists in a distant galaxy to the nearest gram. We do have estimates of the masses of galaxies. The uncertainties in these are large. No one would be surprised if a particular technique was a factor of 2 either too big or too small.
But multiple techniques are used and they agree! No one would be as silly as to think that the masses of galaxies were a factor of 40 too small.

[DSo]

MM,

It’s the 1930’s and guys and gals studying nuclear properties noticed that when a neutron disintegrates into a proton and electron something is wrong. The observed momentums don’t all cancel out. Meaning either conservation of energy, momentum and angular momentum is wrong , or, wait for it … something not directly observed is also part of the picture. I’m sure you know this by now, but along comes a smart guy named Pauli and he postulates that a “little neutral one” or neutrino is the missing piece of the picture above. From the Neutron disintegration reaction, or Beta decay, a great number of the properties of the neutrino can be deduced. The neutrino is subsequently accepted by the nuclear physics community as a fundamental particle and is used in the story of a whole host of other phenomena.

Now here is the crux of the story … All of this was done well BEFORE the neutrino was directly observed.

How is this ANY DIFFERENT from the situation now? And don’t give us the line that neutrinos have been observed in the lab and so forth. BEFORE they we observed, they were postulated to exist and used by scientists to explain observations and measurements.

I challenge you to explain how the current situation with Dark Matter is fundamentally different that the history of the neutrino. How is the hypothesis of Dark Matter not science?

[Michael Mozina]

Now here is the crux of the story … All of this was done well BEFORE the neutrino was directly observed.

How is this ANY DIFFERENT from the situation now?

The *important* difference is that even the very postulation of a neutrinos came about as a direct result of *EMPIRICAL EXPERIMENTS* which directly measured the energy output of the beta decay process. The other particles in the decay process were directly measured in the experiment and the amount of left over energy could *only* (no other possible option existed) be caused by a new particle, or a failure in a "law" of physics. No other particle we had identified could account for that specific amount of energy.

That "unidentified mass" in a distant galaxy could be caused by anything. There was never a "controlled experiment" performed that directly measured the actual normal mass in those galaxies. We simply "estimated" the amount of normal mass in a galaxy based on a whole range of assumptions. That distant missing mass doesn't *REQUIRE* a new form of matter to exist. No laws of physics "require" that we postulate a new and exotic form of matter. Nothing absolutely necessitates that we postulate an exotic new form of matter. Our mass estimates are simply wrong for all we know because our technologies are still very limited. We can't actually "count" the number of stars in a galaxy we "estimate" them based on lots and lots of lots of questionable assumptions.

Whereas neutrinos were discovered (and first postulated) via empirical physics in the lab, SUSY particles have not. Whereas neutrinos were *necessary* to keep laws of physics from being violated, SUSY theory is not. Whereas neutrinos have a known source, SUSY particles do not. There's no comparison because we have not and never could perform a "controlled experiment" to weigh the amount of normal matter in a galaxy. That's the key difference.

[Michael Mozina]

Well for a start, for stars of ~ 1 solar mass the mass luminosity relationship gives:

L/Lsun = (M/Msun)4

Or
M/Msun= (L/Lsun)0.25

So even if we were underestimating the luminosity of a star by a factor of 2, we'd underestimating the mass of the star by a factor of just 1.2. So no, it doesn't make a great deal of difference.

So, just out of curiosity, why did you subjectively decide to assume that there were the same number of point sources (just larger) rather than simply doubling the number of point sources?

[Michael Mozina]

It does have an effect - the intrinsic brightness of many celestial objects may have been underestimated. That is what the paper states.

IMO (as a non-astronomer) I would say that this has *NO* effect whatsoever on our mass estimation of a galaxy.

Baloney! That is physically impossible. Somehow you're going to have to add mass to account for that additional brightness. As TBT notes, even in the most conservative way of "adjusting' the numbers, some adjustment will absolutely be required.

But the mass estimation of galaxies is only one part of the detection of dark matter. Most of the normal matter in the universe turns out to be intergalactic medium, i.e. plasma.

Ya, and evidently it's "twice as dusty" too.

Your whole argument is predicated upon an *accurate* "guestimate" of the amount of "normal" matter in a galaxy, and these recent papers demonstrate that our estimates of normal mass in a galaxy has some
"serious" flaws.

[DeiRenDopa]

[...]
The inverse square nature of (Newtonian) gravitation was confirmed "in the lab" well after the theory was first published.
And again with the ridiculous analogies. Gravity is not shy around a lab. DM never shows up in a lab. See the difference?
I think your (total?) inability to grasp that theories are quantitative means you cannot, and will not, understand this.

What Newton did (among other things) was develop a theory which could account for the observed motions of the Sun, Moon and planets - quantitatively.

Until Newton, no one expected that the heavens would follow rules that are the same as things on the Earth did, and following the MM approach, positing that masses attract each other, according to an inverse square law, is just as much a hypothetical as DM. Today it's easy to link the falling of dense objects, here on the surface of the Earth, with the attraction between two masses (and a force we call 'gravity'); at the time, the idea of 'gravity' (as a shorthand for mutual attraction of masses) was a totally radical idea.

And that's where the testing "in the lab" comes in: this brand new theory of a hypothetical entity called "gravity" was not tested - per MM's worldview - for many decades after the theory was published (indeed, not until well after Newton's death).

GR was not tested "in the lab" until well after it was confirmed as a consistent explanation for several sets of astronomical observations.

Yes ,but again "gravity" shows up here on Earth, and therefore I'm sure it occurs "out there" in space too. I have no doubt that gravity exists and has an effect on matter. Compare and contrast that to your mythical matter.

You're clearly missing the key point DRD. Gravity isn't shy around the lab. I'm therefore happy to let you point at the sky and claim "gravity did it" and I'll consider your math formulas to be "useful" in determining how well your mathematical model matches nature's expression of "gravity". [...]
You realise that you just allowed for a cosmological constant (Λ) explanation for dark energy, don't you? :)

I mean, Λ is part of a math formula for gravity, I can point to the sky and say 'gravity did it', and show that the mathematical model matches nature's expression of gravity very well. :D

[Michael Mozina]

But they didn't at the time they were proposed. What is it that you don't understand about this really really basic argument?

Please read my response to Dso. It's not just a question of "could we empirically demonstrate it" at the moment they were proposed, it's the fact that no laws of physics are at stake without a SUSY particle, and no empirical experiment requires that a SUSY particle exist.

Controlled experiments demonstrate the need for matter that only interacts weakly.

What specific "control" mechanism are you referring to?

[Reality Check]

The *important* difference is that even the very postulation of a neutrinos came about as a direct result of *EMPIRICAL EXPERIMENTS* which directly measured the energy output of the beta decay process.
... snipped non-science stuff,,,.

The *important* similarity is that even the very postulation of dark matter came about as a direct result of *EMPIRICAL EXPERIMENTS* which directly measured

The motion of galaxies in galactic clusters.
The motion of stars in galaxies.
The distribution of matter in galactic clusters.
The distribution of the intergalactic medium in galactic clusters.
Then there are the

*EMPIRICAL EXPERIMENTS* that may have indirectly measured dark matter here on Earth.
*EMPIRICAL EXPERIMENTS* that are being done now to directly measured dark matter here on Earth.

[Reality Check]

Baloney! That is physically impossible. Somehow you're going to have to add mass to account for that additional brightness. As TBT notes, even in the most conservative way of "adjusting' the numbers, some adjustment will absolutely be required.
That is why I said "IMO as a (non-astronomer)".
As TBT notes there will be an insignificant (in terms of astronomical measurements) change in the masses of galaxies. The mass due to main sequence stars will go up by 20%.



You know that (Dark Matter Part I: How Much Matter is There? (http://scienceblogs.com/startswithabang/2009/09/dark_matter_part_i_how_much_ma.php)):
Gravitational measurements show that 25% to 30% of the universe is mass.
The measured mass of stars are only about 0.5% of the mass in the Universe.
The measured mass of the intergalactic medium is 3.6% of the mass in the Universe.
Can you understand that 0.4% is about 60 times less than 25%?


Can you understand that even 1% is less than 25%?

[DeiRenDopa]

It does have an effect - the intrinsic brightness of many celestial objects may have been underestimated. That is what the paper states.

IMO (as a non-astronomer) I would say that this has *NO* effect whatsoever on our mass estimation of a galaxy.Baloney! That is physically impossible. Somehow you're going to have to add mass to account for that additional brightness. As TBT notes, even in the most conservative way of "adjusting' the numbers, some adjustment will absolutely be required.
Once again your (complete?) blindness to (unwillingness to consider?) the quantitative aspects makes your posts ridiculous.

If you truly think that either an environment dependent IMF, or a dustier ISM, or both, renders the results of the many different kinds of observations (each of many different objects, obtained using different techniques) wrt CDM wildly wrong (i.e. out by at least six sigma), then put fingers to keyboard, write a paper, and get it published.

To take just one example: the CDM in a rich cluster is in the IGM, which is where most of the ordinary ("baryonic") mass is too. Is an environment-dependent IMF going to change that? No. Is a dustier ISM in all galaxies in the cluster going to change that? No. (BTW, you do realise, don't you, that massive amounts of dust in the IGM of rich clusters would be screamingly obviously).

Back to Fermi.

AFAIK, the planned Fermi CDM annihilation (or similar) searches concern the MW bulge (and, possibly, the tiny CDM-rich dwarf satellite galaxy Segue I).

Will an environment-dependent IMF substantially reduce the estimated mass of CDM in the MW bulge? No (you do know why, don't you?).

Will a dustier than previously thought ISM substantially reduce the estimated mass of CDM in the MW bulge? No (you do know why, don't you?).

So, wrt the test that this thread is - I guess - supposed to be about, neither of the two recent results which you cite makes any significant difference.

Oh, and don't you think it would be wise to hold off pinning your hopes on just two recent papers ... at least until later ones corroborate their results? You see, as si has pointed out several times, there are essentially three kinds of result from this sort of test; namely, incorrect conclusions (bad data, bad analyses, etc), new models using existing theories, and new theories. With solar system objects, and gravity, there are examples of all three: Pluto (deviations in the orbit of Neptune went away, no tenth planet needed), Neptune (apply Newtonian gravitation), and Vulcan (theory of gravity wrong, GR is better).

But the mass estimation of galaxies is only one part of the detection of dark matter. Most of the normal matter in the universe turns out to be intergalactic medium, i.e. plasma.
Ya, and evidently it's "twice as dusty" too.
No, only the ISM is (or may be) ...

Your whole argument is predicated upon an *accurate* "guestimate" of the amount of "normal" matter in a galaxy, and these recent papers demonstrate that our estimates of normal mass in a galaxy has some
"serious" flaws.
As I have shown, for rich clusters, the mass in the constituent galaxies is pretty much irrelevant.

I could repeat this exercise at a larger scale - cosmology - and the result would be the same ... independent of estimates of the mass of galaxies, there are several sets of independent observations - and analyses - which yield consistent results wrt CDM.

[DSo]

[QUOTE=Michael Mozina;5268198]The *important* difference is that even the very postulation of a neutrinos came about as a direct result of *EMPIRICAL EXPERIMENTS* which directly measured the energy output of the beta decay process.

And what happens to your argument if and when DM particles are observed in experiments here on earth?

[Michael Mozina]

I think your (total?) inability to grasp that theories are quantitative means you cannot, and will not, understand this.

I think your inability to grasp the fact that math alone doesn't demonstrate that something exist in nature means you cannot and will not understand this, but......

It doesn't matter one iota how many many formulas you slap on to the term "God matter". It doesn't matter how many times you point at the sky with those math formulas and claim "God matter did it". Nothing but an empirical demonstration of "God matter" is going to demonstrate that God matter exists and has the properties you claim it has.

What Newton did (among other things) was develop a theory which could account for the observed motions of the Sun, Moon and planets - quantitatively.

Until Newton, no one expected that the heavens would follow rules that are the same as things on the Earth did,

Gah! It's the fact that gravity *DOES* show up on Earth that differentiates "gravity theory" from "God matter theory", not the math!

and following the MM approach, positing that masses attract each other, according to an inverse square law, is just as much a hypothetical as DM.

The existence of gravity is not "hypothetical", it's real and I can experience it personally. That math he came up with could be "right", or it could be "wrong" but the fact that gravity isn't shy around the lab, and it occurs here on Earth, means that we have some hope of confirming or falsifying the math related to any gravity theory. Even if that math (or some other math) is demonstrated to be wrong, "gravity" will not cease to exist in nature, nor will "gravity" stop being a part of "physical reality".

Gravity is *QUALIFIED*, not simply *QUANTIFIED*. Newtons understanding of gravity is quite different than GR, and both of them may one day be replaced with a QM theory about gravity for all I know. In no circumstance will the mathematical model of gravity be the thing that makes it 'real' and makes it have a "real effect" on 'real things". Gravity theories will always enjoy *qualitative* support, even if none of the current mathematical models of gravity survive the next 100 years of technological advancement.

Empirical physics works in a lab even if we don't have a mathematical model to describe it yet. Empirical physics doesn't *NEED* lil ol me to understand the math in order to manifest itself in nature. I can feel gravity and experience gravity, and therefore I have no doubt it is "real", that it "exists in nature" and has some effect on nature, even if I put very little faith in the long term viability of the current mathematical models that describe it.

[Michael Mozina]

And what happens to your argument if and when DM particles are observed in experiments here on earth?

That would depend on what "properties" they are shown to have. If for instance these hypothetical particles immediately decay into some ordinary form of matter, my criticism is still valid. If they interact with light my criticism is still valid. If they dont' pass through ordinary matter my criticisms are still valid.

Those 'properties' that keep getting slapped onto DM theory are purely ad hoc properties that are designed to "fill the gaps" on a "custom fit' basis. They are all "made to fit' an otherwise dead theory in an effort to claim that current galactic mass estimates are correct. Nothing about SUSY particles is known, not even if they exist. IMO the odds that they exist at all is low, but definitely worth "checking" anyway. I certainly support the LHC experiments that are designed to look for them.

The odds however that something does exist and has all those ad hoc properties is highly unlikely IMO. It's a lot more likely that we simply blew the mass estimates in a big way and we simply don't have clue how to fix it and our technology is still pretty limited.

If and when we find some SUSY particles and if and when they are shown to have all those claimed properties, then it would be appropriate IMO to point at the sky and claim SUSY particles did it. Until then you compounding hypothetical properties on top of hypothetical entities. That is a religion IMO, not 'science".

[DeiRenDopa]

Now here is the crux of the story … All of this was done well BEFORE the neutrino was directly observed.

How is this ANY DIFFERENT from the situation now?The *important* difference is that even the very postulation of a neutrinos came about as a direct result of *EMPIRICAL EXPERIMENTS* which directly measured the energy output of the beta decay process.
Approx two decades earlier the reverse ... the postulation of GR came about as a direct result of ... what? Certainly no "in the lab" experiments!

The other particles in the decay process were directly measured in the experiment and the amount of left over energy could *only* (no other possible option existed) be caused by a new particle, or a failure in a "law" of physics. No other particle we had identified could account for that specific amount of energy.
Fast reverse to a couple of decades prior ...

The success of Newtonian gravitation in finding Neptune was known to all, and some patchy success seemed to be in hand wrt finding Vulcan (to account for the anomalies in Mercury's orbit). Along comes a radical new theory (of gravity), and claims to be able to account for the anomalies in Mercury's orbit. But, to the MM clones of the day, this radical new idea cannot be tested "in the lab". By the MM definition, it is purely hypothetical ... and the 1919 solar eclipse expeditions? What a joke! The existing theory accounted for the results just as well ...

That "unidentified mass" in a distant galaxy could be caused by anything. There was never a "controlled experiment" performed that directly measured the actual normal mass in those galaxies.
Nor will there ever be ... so all astrophysics is non-science?

We simply "estimated" the amount of normal mass in a galaxy based on a whole range of assumptions. That distant missing mass doesn't *REQUIRE* a new form of matter to exist.
Think early years of the 20th century, think GR ... the anomalies in Mercury's orbit, and the solar eclipse observations do not *REQUIRE* a new form of geometry to exist.

No laws of physics "require" that we postulate a new and exotic form of matter. Nothing absolutely necessitates that we postulate an exotic new form of matter. Our mass estimates are simply wrong for all we know because our technologies are still very limited. We can't actually "count" the number of stars in a galaxy we "estimate" them based on lots and lots of lots of questionable assumptions.
Just as one does not require forces, momenta, energy, work, etc, etc, etc ... angels and fairies and demons will do just fine to explain the observed behaviour of the real world (i.e. your description is not one that includes science ...)

Whereas neutrinos were discovered (and first postulated) via empirical physics in the lab, SUSY particles have not.
So between ~1930 and 1957, no observed neutrinos.

Perhaps it will be next year that SUSY particles are observed "in the lab"?

Perhaps it will be within a decade that MW DM particles are observed in underground detectors?

Helium was first postulated via observations of the Sun (it was later found here on Earth); certain meta-stable states of doubly ionised oxygen are postulated via observations of nebulae (and application of quantum mechanics), none has been observed "in the lab".

Whereas neutrinos were *necessary* to keep laws of physics from being violated, SUSY theory is not.
GR was not *necessary* to keep laws of physics from being violated.

Whereas neutrinos have a known source, SUSY particles do not. There's no comparison because we have not and never could perform a "controlled experiment" to weigh the amount of normal matter in a galaxy. That's the key difference.
Just so that I don't misunderstand ... because (Newtonian) gravity can account for the observed motions of the planets (etc) is completely irrelevant - we have not, and never will, be able to perform a "controlled experiment" with planets "in the lab". Did I get it right?

[DSo]

That is a religion IMO, not 'science".


So all the people working in this field are practicing religion then? Oh, but wait if their ideas turn out to be validated in the lab then it is science?

Weird logic. What's your point in all of this?

[DeiRenDopa]

I think your inability to grasp the fact that math alone doesn't demonstrate that something exist in nature means you cannot and will not understand this, but......

It doesn't matter one iota how many many formulas you slap on to the term "God matter". It doesn't matter how many times you point at the sky with those math formulas and claim "God matter did it". Nothing but an empirical demonstration of "God matter" is going to demonstrate that God matter exists and has the properties you claim it has.
So if you'd been on the relevant "Royal" society of the time, you'd have canned Newton's work?

[...]
Until Newton, no one expected that the heavens would follow rules that are the same as things on the Earth did,

Gah! It's the fact that gravity *DOES* show up on Earth that differentiates "gravity theory" from "God matter theory", not the math!
Um ... did you miss the part about how "gravity" did not mean - then - what it means today?

Did you not grasp that - until Newton - "gravity" was not a physical law, a law of nature, a natural force, ....?

The thing which you insist "*DOES* show up on Earth" is a theoretical explanation for a bunch of observations ... no reason to suppose it has anything to do with mass, rather than, say, the spirits of Earth and Water (and the spirits of Fire and Air are ruled by quite different gods).

Did you also miss the part about dark energy (in the form of Λ) being just as much "gravity" (which shows up here on Earth) as a ball of lead?


and following the MM approach, positing that masses attract each other, according to an inverse square law, is just as much a hypothetical as DM.
The existence of gravity is not "hypothetical", it's real and I can experience it personally.
Not so.

What is real, and what you experience, are the spirits of Earth and Water; "gravity" is a piece of hypothetical fiction, merely some magic math nonsense dreamed up by someone with far too much idle time on their hands.

The planets travel on their courses due to the rules of the heavens, beyond the reach of even the spirits of Fire and Air.

That math he came up with could be "right", or it could be "wrong" but the fact that gravity isn't shy around the lab, and it occurs here on Earth, means that we have some hope of confirming or falsifying the math related to any gravity theory. Even if that math (or some other math) is demonstrated to be wrong, "gravity" will not cease to exist in nature, nor will "gravity" stop being a part of "physical reality".
You have obviously been far too heavily influenced by these natural philosophers ... I tell you again, "gravity" does not exist, it is a fiction, hypothetical ... what makes heavy things fall is their Earth spirits; what makes things rise is their Air (or sometimes Fire) spirits.

Gravity is *QUALIFIED*, not simply *QUANTIFIED*. Newtons understanding of gravity is quite different than GR, and both of them may one day be replaced with a QM theory about gravity for all I know. In no circumstance will the mathematical model of gravity be the thing that makes it 'real' and makes it have a "real effect" on 'real things". Gravity theories will always enjoy *qualitative* support, even if none of the current mathematical models of gravity survive the next 100 years of technological advancement.

Empirical physics works in a lab even if we don't have a mathematical model to describe it yet. Empirical physics doesn't *NEED* lil ol me to understand the math in order to manifest itself in nature. I can feel gravity and experience gravity,
You keep banging on about this hypothetical nonsense!

You CANNOT "feel gravity", you CANNOT "experience gravity"! :mad:

What you feel, and experience, is the Earth spirits.

and therefore I have no doubt it is "real", that it "exists in nature" and has some effect on nature, even if I put very little faith in the long term viability of the current mathematical models that describe it.
Perhaps it's time for you to tell us all what "gravity" is?

[Michael Mozina]

So if you'd been on the relevant "Royal" society of the time, you'd have canned Newton's work?

No, I would have said: Well Sir Isaac, I can certainly feel "gravity' as you call it so your gravity theory is well "qualified", and I can see that your quantitative work applies very well here on Earth in empirical experiments too. I can't say for sure that the planets and stars work as you claim they do or that your math will stand the test of time, but "bravo".

Um ... did you miss the part about how "gravity" did not mean - then - what it means today?

Did you not grasp that - until Newton - "gravity" was not a physical law, a law of nature, a natural force, ....?

But we all experience it. Did you miss that part about the fact I can "experience" "gravity" here on Earth? Did you notice that a rock in the lab experiences it too? Did you miss that part about how I can "feel" it and "see' it have an effect here on Earth and therefore I have no problem with you mathematically quantifying it, and I can check your work if I want to? It doesn't even matter one iota whether I "percieve" it as a "force" or a "curvature", I do in fact "feel" gravity every single day. It's fully "qualified" in every empirical way. FYI, I'm not really interested in how you personally think other people thought of gravity prior to Newton. That sounds like a useless trip down denial lane. We experience gravity. It's well "qualified" and shows up in real labs on Earth.

"Electrical current" is also highly "qualified". We can see it's direct effect on plasma in lab. You are therefore welcome to point at the sky and claim "electricity did it" if you like. You might be right or wrong, but at least it's a well "qualified" theory. I know from empirical experiments that neutrinos exist so you're welcome to point at the sky and claim neutrinos did it too. Ditto on the right or wrong aspect, but at least I won't cry foul about a lack of qualification.

I can't see any empirical evidence to suggest that SUSY particles exist or have any of the various properties that you suggest. You can't show me a single controlled instance of a bit of dark matter generating one single gamma ray on Earth, but you expect me to believe "dark matter spirits in the sky did it." Notice a key difference related to *qualification*?

[Michael Mozina]

So all the people working in this field are practicing religion then?

In the sense that proponents of Lambda-CDM hold beliefs that are predicated upon multiple leaps of faith in 'unseen entities', yes, it's 96% religion in fact.

Oh, but wait if their ideas turn out to be validated in the lab then it is science?

How would that be different from any other 'religion' in your opinion?

Weird logic. What's your point in all of this?

My point of all this is that we know for a fact that FERMI sees our own sun. We know for a fact that suns and planets emit gamma rays in space. We know that every galaxy contains hundreds of billions of such objects. We know that Thomson and Compton scattering happen and that space is "dusty". We know our universe is huge and our technology is still rather primitive. If there really is any valid reason why you expect me to believe 'dark matter did it", I'd like to see some evidence. So far all I see are handwaves and a lot of silly nonsense about how all these properties "could be" found and *one day" your "religion" might become a "science". I think any "believer" in anything could say exactly that same statement, so I really don't see how you figure it's a helpful or useful argument.

My point is that "dark matter" isn't necessary. It's not likely. It's not even empirically supported in a single instance on Earth, not ever. On the other hand "electrical discharges" do release these wavelengths of light and we see them coming from every major body in our solar system. It's hardly surprising then that FERMI sees gamma rays from our galaxy and there is no evidence at all that anything seen in Fermi images has anything at all to do with "dark matter". There's no empirical connection. It's all a giant "act of faith".

[DSo]

My point of all this is that we know for a fact that FERMI sees our own sun. We know for a fact that suns and planets emit gamma rays in space. We know that every galaxy contains hundreds of billions of such objects. We know that Thomson and Compton scattering happen and that space is "dusty". We know our universe is huge and our technology is still rather primitive. If there really is any valid reason why you expect me to believe 'dark matter did it", I'd like to see some evidence. So far all I see are handwaves and a lot of silly nonsense about how all these properties "could be" found and *one day" your "religion" might become a "science". I think any "believer" in anything could say exactly that same statement, so I really don't see how you figure it's a helpful or useful argument.

My point is that "dark matter" isn't necessary. It's not likely. It's not even empirically supported in a single instance on Earth, not ever. On the other hand "electrical discharges" do release these wavelengths of light and we see them coming from every major body in our solar system. It's hardly surprising then that FERMI sees gamma rays from our galaxy and there is no evidence at all that anything seen in Fermi images has anything at all to do with "dark matter". There's no empirical connection. It's all a giant "act of faith".


That's not a point. That's a rant. Maybe even a rant against modern science?

What are you trying to accomplish after 100's of posts on this subject?

[Michael Mozina]

That's not a point. That's a rant. Maybe even a rant against modern science?

What are you trying to accomplish after 100's of posts on this subject?

I'm trying to convert you all to form of empirical physics called "EU theory". :)

[Michael Mozina]

I mean, Λ is part of a math formula for gravity, I can point to the sky and say 'gravity did it', and show that the mathematical model matches nature's expression of gravity very well. :D

Now all you have to empirically demonstrate is your claim that gravity does repulsive tricks. :)

[DeiRenDopa]

I'm trying to convert you all to form of empirical physics called "EU theory". :)
Well, if that's true, then you're doing a sterling job ... of persuading readers that "EU theory" is, at best, pseudo-science (if not actually anti-science) ...

[Michael Mozina]

The *important* similarity is that even the very postulation of dark matter came about as a direct result of *EMPIRICAL EXPERIMENTS* which directly measured

Sorry, I missed this earlier. Evidently you don't comprehend the difference between a "controlled experiment' with real control mechanisms, and a "simple observation" where no control mechanism are involved.

The motion of galaxies in galactic clusters.

All that demonstrates is that we blew our mass estimates.

The motion of stars in galaxies.

Ditto

The distribution of matter in galactic clusters.

Ditto.

The distribution of the intergalactic medium in galactic clusters.

Then there are the
*EMPIRICAL EXPERIMENTS* that may have indirectly measured dark matter here on Earth.

Such as? If you're referring to neutrinos, neutrinos already have a proper scientific name.

*EMPIRICAL EXPERIMENTS* that are being done now to directly measured dark matter here on Earth.
[/LIST]

That seems to be your one and only rational response IMO. Of course even here you evidently "assume" or "have faith" in the idea that not only will they find such a thing, it will also just happen to have all those specific properties you need it to have. That's quite a leap of faith.

[DeiRenDopa]

No, I would have said: Well Sir Isaac, I can certainly feel "gravity' as you call it so your gravity theory is well "qualified", and I can see that your quantitative work applies very well here on Earth in empirical experiments too.(bold added)

Such as? The ones on "gravity", I mean ...

BTW, are you sure Newton - or any of his contemporaries - would know what you're talking about ("I can certainly feel "gravity' as you call it")?

I can't say for sure that the planets and stars work as you claim they do or that your math will stand the test of time, but "bravo".
Um ... did you miss the part about how "gravity" did not mean - then - what it means today?

Did you not grasp that - until Newton - "gravity" was not a physical law, a law of nature, a natural force, ....?
But we all experience it.
No we don't.

How many times to I have to tell you!

When you fall, it's the Earth spirits.

When you rise, when submerged in water, it's the Water spirits.

When hot air rises, it's the Air spirits, infused with Fire spirits.

And so on ...

What you "experience" is falling, or rising (when submerged in water), or floating (when on water). The feelings are quite different, and distinct.

Further, your experience is a poor guide ... how do you think flight simulators (to take just one example) give you the fully authentic feeling of falling? of accelerating upwards ('against gravity')?

Did you miss that part about the fact I can "experience" "gravity" here on Earth? Did you notice that a rock in the lab experiences it too?
If said rock is floating in mercury, it is not experiencing gravity.

The leaves in my back yard, on a windy day, do not experience gravity.

The fish in my neighbour's aquarium do not experience gravity.

And so on.

"Gravity" is hypothetical, something made up by natural philosophers ...

Did you miss that part about how I can "feel" it and "see' it have an effect here on Earth and therefore I have no problem with you mathematically quantifying it, and I can check your work if I want to? It doesn't even matter one iota whether I "percieve" it as a "force" or a "curvature", I do in fact "feel" gravity every single day. It's fully "qualified" in every empirical way. FYI, I'm not really interested in how you personally think other people thought of gravity prior to Newton. That sounds like a useless trip down denial lane.
Actually, it's an interesting example of how easily we fully internalise the results of centuries of physics, and how hard it is to recognise that things like "gravity" are not what we experience, or feel ...

We experience gravity. It's well "qualified" and shows up in real labs on Earth.

"Electrical current" is also highly "qualified". We can see it's direct effect on plasma in lab.
Same deal, ditto wrt interactions mediated by gluons and the W's and the Z, ...

You are therefore welcome to point at the sky and claim "electricity did it" if you like. You might be right or wrong, but at least it's a well "qualified" theory. I know from empirical experiments that neutrinos exist
But you didn't, certainly not before 1930 ... and you may know that SUSY particles exist too, perhaps as early as 2011 ...

so you're welcome to point at the sky and claim neutrinos did it too. Ditto on the right or wrong aspect, but at least I won't cry foul about a lack of qualification.
That's great news! :)

So there will be no more screeds denouncing the Λ version of dark energy, nor any cosmological models which incorporate it? After all, Λ is merely one part of a mathematical equation which describes gravity, and can be shown to exist, by pointing to things in the sky ...

I can't see any empirical evidence to suggest that SUSY particles exist or have any of the various properties that you suggest.
But the day they turn up in LHC experimental results you will, right?

And the day XENON (or another DM detector) records DM particle footprints you will, right?

You can't show me a single controlled instance of a bit of dark matter generating one single gamma ray on Earth, but you expect me to believe "dark matter spirits in the sky did it." Notice a key difference related to *qualification*?
No I can't, and don't, see that ... "gravity" is purely hypothetical, as is "electric current". All you are doing is cherry picking from the centuries of physics that which you wish to call "*qualification*"; this is not objective, is not independently verifiable, and is internally inconsistent.

IOW, the very antithesis of science.

[Michael Mozina]

Well, if that's true, then you're doing a sterling job ... of persuading readers that "EU theory" is, at best, pseudo-science (if not actually anti-science) ...

Ya right, talk about political spin doctoring.

Electrical discharges show up in a lab DRD, so unlike your beloved dead inflation deity, your dark evil energy theories and your dark matter invisible stuff, EU theory cannot ever be a form of pseudo-science. How could *ANYTHING* be worse that 96% metaphysics?

In any given application, EU theory could be right or it could be wrong, but electricity definitely shows up in a lab and in nature. You might whine about quantification, or lack thereof, but you can't even dispute the fact that electrical discharges emit gamma rays in nature, right here on Earth and many places inside this solar system. As it relates to what we observe in Fermi images, electrical discharge theory will always be a "better" scientific theory than "dark matter did it".

[Tubbythin]

So, just out of curiosity, why did you subjectively decide to assume that there were the same number of point sources (just larger) rather than simply doubling the number of point sources?

I didn't. You said:
If it's "twice as bright" as we realized, why wouldn't that equate to a doubling of the number of stars and solar systems in a galaxy?

I was giving some indication of why.
Have your factor of 2 for all I care. You've successfully shown that even if we have made such a mistake, DM is still an absolute necessity.

[Michael Mozina]

But you didn't, certainly not before 1930 ... and you may know that SUSY particles exist too, perhaps as early as 2011 ...

But the day they turn up in LHC experimental results you will, right?

Most of that last post isn't worth responding to, but this comment warrants a response. Unlike the dead inflation deity, 'dark matter' does have one redeeming quality. It's existence or lack thereof can be' put to a real empirical test. What's going to happen if 2013,14,15 roll around and there's no confirmation of a SUSY particle? What then? Will you 'give up your faith"? Will you accept that "electrical discharges" might be the real culprit of some distant gamma rays?

When you can show me some something more than some math formula, and you have some empirical physics to compare it with, let me know. Let me know if it has all those nifty properties you keep assigning to it, like longevity and gamma ray vision and the ability to pass through walls in a single bound. Until that time your beliefs are based upon blind faith in 'unseen things'.

[Tubbythin]

Please read my response to Dso. It's not just a question of "could we empirically demonstrate it" at the moment they were proposed, it's the fact that no laws of physics are at stake without a SUSY particle, and no empirical experiment requires that a SUSY particle exist.

Very well:


The *important* difference is that even the very postulation of a neutrinos came about as a direct result of *EMPIRICAL EXPERIMENTS* which directly measured the energy output of the beta decay process.
This isn't a difference. The requirement of DM comes from "*EMPIRICAL EXPERIMENTS*" that measure the mass in visible matter, the distribution of mass in visible matter, the mass in invisible matter and the distribution of mass in invisible matter.


The other particles in the decay process were directly measured in the experiment and the amount of left over energy could *only* (no other possible option existed) be caused by a new particle, or a failure in a "law" of physics.


No other particle we had identified could account for that specific amount of energy.
No known SM particles or MACHO objects can account for the galactic rotation curves and cluster rotation curves.


That "unidentified mass" in a distant galaxy could be caused by anything.
This is of course so blatantly false I won't bother to say anymore.


There was never a "controlled experiment" performed that directly measured the actual normal mass in those galaxies.
There have been plenty.


We simply "estimated" the amount of normal mass in a galaxy based on a whole range of assumptions.
Independent measurements give the same results. Even the error bars imposed by any simplifying assumptions cannot possibly account for the roation curves. Remember, these rotation curves don't only tell us how mcuh but in what distribution the DM is found.


That distant missing mass doesn't *REQUIRE* a new form of matter to exist.
Yes, it does.


No laws of physics "require" that we postulate a new and exotic form of matter.
Sure we do. If we want to keep our law of gravity that is absolutely what we must do. There is simply no other alternative that is consistent with the observational facts.


Nothing absolutely necessitates that we postulate an exotic new form of matter.
Well no. We could change out law of gravity. But you don't want to do that either.


Our mass estimates are simply wrong for all we know because our technologies are still very limited. We can't actually "count" the number of stars in a galaxy we "estimate" them based on lots and lots of lots of questionable assumptions.
Then how come different, independent mass estimates agree? How come the different mass distribution measurements agree? The discrepancy between the visible matter and the galactic roation curves isn't even particularly difficult to see. It can probably be done in an undergrad lab.


Whereas neutrinos were discovered (and first postulated) via empirical physics in the lab, SUSY particles have not.
The Universe is our lab Michael. Unless you want to reject the whole of astronomy.


Whereas neutrinos were *necessary* to keep laws of physics from being violated, SUSY theory is not.
Not specifically SUSY, no. But some kind of non-SM particle.


Whereas neutrinos have a known source, SUSY particles do not.
Sure they do. They'd be residues of the Big Bang. Just like most of the helium we have in the Universe. Now, remind us. How was helium discovered?


There's no comparison because we have not and never could perform a "controlled experiment" to weigh the amount of normal matter in a galaxy. That's the key difference.
Sure we can. Its been done.You just have no idea what "controlled experiment" means.


What specific "control" mechanism are you referring to?
Take your pick. Say... measuring the radial profile of HI in a spiral galaxy. Please explain to everyone how this is not a controlled experiment.

By the way, don't think I haven't noticed that you completely ignored my corrections to your wild assertions about physicists making wild assertions

Let's recap:

Correction: One of the things you *NEED* from you ad hoc gap filler is longevity because without it, your theory is toast. You therefore "made up" a "necessary property" for your mythical gap filler, in this case longevity.
Completely wrong. The properties of SUSY particles come QM, not from DM.


It was a property you created based on *NEED* not upon "observation" in a lab.
Nope. Completely wrong. The properties of SUSY particles come QM, not from DM.


Even if we do ever find a SUSY particle in a collider experiment, how do you know it's going to last even a full millisecond before reverting into something we already know about? Pure faith? Ad hoc need? What?
Nope. Completely wrong. Many (most?) SUSY theories have a lightest stable particle. This is a conclusion drawn from QM plus the SM, not from DM observations.

Now, are you going to retract your wild, ignorant, stupid and completely wrong allegations?

[Tubbythin]

Ya right, talk about political spin doctoring.

Electrical discharges show up in a lab DRD, so unlike your beloved dead inflation deity, your dark evil energy theories and your dark matter invisible stuff, EU theory cannot ever be a form of pseudo-science. How could *ANYTHING* be worse that 96% metaphysics?
The only one bringing in metaphysics is you. Now please stop it or go over to the religion and philosophy forum.


In any given application, EU theory could be right or it could be wrong, but electricity definitely shows up in a lab and in nature. You might whine about quantification, or lack thereof, but you can't even dispute the fact that electrical discharges emit gamma rays in nature, right here on Earth and many places inside this solar system. As it relates to what we observe in Fermi images, electrical discharge theory will always be a "better" scientific theory than "dark matter did it".
Nope. We can quantitatively rule out electrical discharges do it. We cannot quantitatively rule out DM. Therefore EU is unequivocally wrong, independent of the validity (or otherwise) of DM theories.

[Tubbythin]

All that demonstrates is that we blew our mass estimates.
Nope. Multiple indpendent experiments show the same results. Therefore we clearly did not blow our mass estimates.


Ditto

Ditto.


Ditto.

Ditto.


Such as? If you're referring to neutrinos, neutrinos already have a proper scientific name.
They're still dark.


That seems to be your one and only rational response IMO. Of course even here you evidently "assume" or "have faith" in the idea that not only will they find such a thing, it will also just happen to have all those specific properties you need it to have. That's quite a leap of faith.
I don't see how its a leap of faith in the slightest. For example, if SUSY turns out to be a good theory then SUSY particles will have to have the properties given to them by the SUSY theory in question. Since most SUSY theories have a lightest stable particle in the TeV range it is quite obviously highly probable that we will find a lightest stable particle in the TeV range. This is not faith in any way shape or form. In fact its bordering on tautolgically obvious.

[DeiRenDopa]

I mean, Λ is part of a math formula for gravity, I can point to the sky and say 'gravity did it', and show that the mathematical model matches nature's expression of gravity very well. Now all you have to empirically demonstrate is your claim that gravity does repulsive tricks. :)

Not at all ... after all, you fully accepted that GR worked just as well, as a description of gravity, simply because it could account for the anomalies in the observed positions of Mercury (on the sky) ... and the "in the lab" tests of GR - fully six+ decades later - did not, in any way shape or form, involve testing advances of perihelia of planets ...

IOW, this is - yet another - example of the subjective, idiosyncratic, internally inconsistent nature of the MM worldview of physics ...

[Reality Check]

Sorry, I missed this earlier. Evidently you don't comprehend the difference between a "controlled experiment' with real control mechanisms, and a "simple observation" where no control mechanism are involved.

Apparently you don't comprehend that the difference between a "controlled experiment' with real control mechanisms, and a "simple observation" where no control mechanism are involved are trivial.
An observation is just as empirical as a controlled experiment.
The main difference is that the universe may not allow an observation to be repeated many times, e.g. there are currently only three observations of dark matter separated from normal matter: Bullet Cluster (http://chandra.harvard.edu/photo/2006/1e0657/),MACS J0025.4-1222 (http://hubblesite.org/newscenter/archive/releases/2008/32/) and Abell 520 (http://en.wikipedia.org/wiki/Abell_520).

I am not sure how many galactic clusters have has their mass distributions measured (more evidence of dark matter).



All that demonstrates is that we blew our mass estimates.

Wrong.
All that demonstrates is that you want the mass estimates to be blown and are prepared to ignore the actual measurements.

As in my next post:


You know that (Dark Matter Part I: How Much Matter is There? (http://scienceblogs.com/startswithabang/2009/09/dark_matter_part_i_how_much_ma.php)):
Gravitational measurements show that 25% to 30% of the universe is mass.
The measured mass of stars are only about 0.5% of the mass in the Universe.
The measured mass of the intergalactic medium is 3.6% of the mass in the Universe.
Can you understand that 0.4% is about 60 times less than 25%?
Can you understand that even 1% is less than 25%?


Ditto

As above.


Ditto

Your ignorance that this measurement is done using gravitation lensing and measure all of the mass of the cluster is astounding.
You have been told this many times and still cannot understand it.


Ditto

Your ignorance that this measurement is done using X-ray observations is astounding.
You have been told this several times and still cannot understand it.


Such as? If you're referring to neutrinos, neutrinos already have a proper scientific name.

Dark Matter (detection) (http://en.wikipedia.org/wiki/Dark_matter#Detection)


That seems to be your one and only rational response IMO. Of course even here you evidently "assume" or "have faith" in the idea that not only will they find such a thing, it will also just happen to have all those specific properties you need it to have. That's quite a leap of faith.
There is no leap of faith needed.
The evidence for the existence of dark matter is overwhelming to any intelligent person. There are possible compositions of dark matter that could be detected here on Earth. So it is a good idea to look for dark matter to see if the composition can be confirmed. That is how science works.

[Michael Mozina]

I didn't. You said:


I was giving some indication of why.
Have your factor of 2 for all I care. You've successfully shown that even if we have made such a mistake, DM is still an absolute necessity.

Understood. FYI, I've come to respect you a great deal through our conversations the last few months and I appreciate your candor and fair minded attitude. Please put yourself in my skeptical shoes here for just a second.

First we find that we may be able to double the number of point sources in a galaxy, effectively doubling the amount of ordinary mass in a galaxy. We also have some evidence that we may have also underestimated the number of small stars in a galaxy compared to the number of larger ones. Both of these pieces of relatively new information suggest that we could easily double or triple the amount of normal matter in a galaxy, simply by changing a few of the variables.

"Missing mass" is still a necessity, but then we have evidence that a lot of the newly discovered missing mass is normal matter. For all we know all of the missing mass is contained in ordinary matter. "Missing mass" is a "necessity" for the time being due to limits of our technology, but SUSY theory is still entirely without merit.

There are hundreds of billions of stars and a galaxy and we may need to double or triple that number just to explain what we've seen so far. That type of "solution' to a "missing mass" problem is also congruent with the presence of additional gamma rays coming from additional suns and planets in the solar systems. We now have a very simple way to explain additional gamma rays, and a lot of that "missing mass" we're looking for. Any sort of Occum's razor argument is going to effectively destroy a "dark matter" solution to a surplus gamma ray problem IMO.

I really do not see a logical or sound reason to believe that any of the gamma rays seen in Fermi images have anything at all to do with "dark matter". I see lots of evidence to suggest that we grossly underestimate the number of point sources in a given galaxy and I see lots of evidence that know sources of energy (like discharges) are fully capable of explaining what we observe.

[Michael Mozina]

Not at all ... after all, you fully accepted that GR worked just as well, as a description of gravity, simply because it could account for the anomalies in the observed positions of Mercury (on the sky) ... and the "in the lab" tests of GR - fully six+ decades later - did not, in any way shape or form, involve testing advances of perihelia of planets ...

IOW, this is - yet another - example of the subjective, idiosyncratic, internally inconsistent nature of the MM worldview of physics ...

Er, no. It's another fine example of you making another ridiculous claim (gravity does repulsive tricks) that you simply cannot and will not even attempt to demonstrate in any empirical manner. Evidently you believe that if you stuff "magic energy" into a "blunder theory", "magic energy" is now part of "gravity". Without empirical support, forget it. Show me empirically that gravity is anything other than attractive in a controlled experiment.

[DeiRenDopa]

[...]

First we find that we may be able to double the number of point sources in a galaxy, effectively doubling the amount of ordinary mass in a galaxy.
Then you need to re-read the paper (not the PR) ... an environment-dependent IMF may "double the number of point sources" in a minority of galaxies (perhaps 30%? 5%?). It won't change the number significantly in galaxies like the MW ...

We also have some evidence that we may have also underestimated the number of small stars in a galaxy compared to the number of larger ones.
Ditto (though the types of galaxies, and regions in them, where this might be true, are different).

Both of these pieces of relatively new information suggest that we could easily double or triple the amount of normal matter in a galaxy, simply by changing a few of the variables.
Poppycock.

Earlier I suggested that you might like to put fingers to keyboard, and write a paper; I will suggest that you do it again, but with a different objective in mind.

If you genuinely think this, you should have little difficulty crunching the numbers, and writing up at least the draft of a paper showing it ...

"Missing mass" is still a necessity, but then we have evidence that a lot of the newly discovered missing mass is normal matter.
In terms of grams, yes, it is a lot.

As a percentage of the current estimates of total 'normal' (baryonic) mass, I'd be surprised if it is greater than one sigma wrt current estimated total mass (with some possible exceptions, e.g. some dwarf galaxies).

For all we know all of the missing mass is contained in ordinary matter.
If you still - after the hundreds and hundreds of posts spent trying to educate you on this - think so, then it truly is hopeless.

If, in fact, you still think so, then by all means spend the time you'd otherwise spend writing empty posts (here and in other internet fora) working on a paper which shows this. Otherwise, when you're in a hole, stop digging.

"Missing mass" is a "necessity" for the time being due to limits of our technology, but SUSY theory is still entirely without merit.

There are hundreds of billions of stars and a galaxy and we may need to double or triple that number just to explain what we've seen so far. That type of "solution' to a "missing mass" problem is also congruent with the presence of additional gamma rays coming from additional suns and planets in the solar systems.
Ya know MM, repeating the same subjective, idiosyncratic, internally inconsistent nonsense doesn't make it less so, merely by repetition.

Let's see your calculations (and numbers) ...

We now have a very simple way to explain additional gamma rays, and a lot of that "missing mass" we're looking for. Any sort of Occum's razor argument is going to effectively destroy a "dark matter" solution to a surplus gamma ray problem IMO.
And your "O" has been shown - a dozen times or more - to be the very antithesis of science ...

I really do not see a logical or sound reason to believe that any of the gamma rays seen in Fermi images have anything at all to do with "dark matter". I see lots of evidence to suggest that we grossly underestimate the number of point sources in a given galaxy and I see lots of evidence that know sources of energy (like discharges) are fully capable of explaining what we observe.
Blah, blah, blah ... numbers, MM, numbers ... where are the numbers?

[Michael Mozina]

Apparently you don't comprehend that the difference between a "controlled experiment' with real control mechanisms, and a "simple observation" where no control mechanism are involved are trivial.

Well, there is your problem in a nutshell for all the world to see. The distinctions are anything but "trivial". The fact you think they are trivial is what lead to your anomalous results IMO.

An observation is just as empirical as a controlled experiment.
The main difference is that the universe may not allow an observation to be repeated many times,

You forgot the whole "cause/effect" benefit of "controlled experiments". Birkeland wanted to demonstrate that the "cause" of the aurora was "electrical current". He built "controlled experiments" where he could change variables and see the results in his empirical tests. In that way he demonstrated an empirical link between "current flow" and aurora. You can't do that with pure observation, you can't necessarily isolate a "cause".

That applies here as it relates to the "cause" of the gamma rays. You "assume" a cause which *NEVER* has occurred here on Earth that you can demonstrate whereas I have assumed a "cause" I have seen demonstrated on Earth thousands of times.

I am not sure how many galactic clusters have has their mass distributions measured (more evidence of dark matter).

It's evidence of "missing mass" or 'unidentified mass'. Just because you can't identify it yet does no automatically require it be a new form of matter, anymore than an "unidentified flying object" in the sky is *necessarily* from another planet. You're going *way* out on a limb by making a new claim about it being in a form of matter you can't support empirically.

There is no leap of faith needed.

Yes there is. The leap of faith is similar to the UFO scenario. You are assuming that because we cannot identify the object, it must *NECESSARILY* be from another planet. In my analogy, yes, it's currently "unidentified", but it could be (and probably is) from *THIS* planet. You're making a huge assumption to claim that the missing mass is anything other than ordinary matter.

The evidence for the existence of dark matter is overwhelming to any intelligent person.

Ah, here's where the ridicule begins? What up with that? If you can't beat me via empirical physics, try a personal attack? You must be getting desperate.

There are possible compositions of dark matter that could be detected here on Earth. So it is a good idea to look for dark matter to see if the composition can be confirmed. That is how science works.

Sure but you refused to consider that fact that the missing mass could be ordinary matter. You refused to actually "confirm" any of the properties of your metaphysical brand of "dark matter". You simply "assumed" all of them on an "as needed" basis to fill the gaps of your otherwise failed mass calculation theory. Even when there is evidence presented to you that we may have underestimated the number of stars in galaxies by a large factor, you still *assume* that new and exotic matter is necessary or required. Why?

[DeiRenDopa]

Er, no. It's another fine example of you making another ridiculous claim (gravity does repulsive tricks) that you simply cannot and will not even attempt to demonstrate in any empirical manner. Evidently you believe that if you stuff "magic energy" into a "blunder theory", "magic energy" is now part of "gravity". Without empirical support, forget it. Show me empirically that gravity is anything other than attractive in a controlled experiment.
Now we're into repeat mode ...

EITHER you trash GR, because it cannot be demonstrated "in the lab", and insist that astronomers try harder to find Vulcan.

OR you accept that GR is a better theory of gravity (than Newton's) BECAUSE it can do the numbers on the sky, DESPITE the fact that no one can demonstrate it "in the lab"*

If you take the first stance, then Newton goes in the round file, way back when; if you take the second, then Λ is a perfectly acceptable component of a theory of gravity.

To make any other claims is to be purely subjective, idiosyncratic, and internally inconsistent ... i.e. to be advocating non-science.

Which is it to be, MM? Science, or nonsense?

* remember that many of the older physicists, in 1918, were dead by the time of Pound/Rebka

[DeiRenDopa]

[...]

Sure but you refused to consider that fact that the missing mass could be ordinary matter.
Dude, your gross ignorance is showing.

There is ~seven decades of effort, strenuous effort, spent on exactly this.

Only after all such avenues had been investigated, and came up empty, did CDM really come into its own. IIRC, one of the first sets of HST observations was aimed at determining if there were sufficient red dwarfs in the halo to account for the known missing mass ... there weren't (and MACHO, OGLE, etc, etc, etc subsequently, and independently, verified this result).

You refused to actually "confirm" any of the properties of your metaphysical brand of "dark matter".
Again, your gross ignorance is showing ... I really have to repeat the details, yet again?

You simply "assumed" all of them on an "as needed" basis to fill the gaps of your otherwise failed mass calculation theory. Even when there is evidence presented to you that we may have underestimated the number of stars in galaxies by a large factor, you still *assume* that new and exotic matter is necessary or required. Why?
Um, er, because the numbers don't lie?

Oh wait, I forgot, you place no store in numbers ... hey MM, did you know that on the fifth Sunday of every month, g, the local acceleration due to gravity, drops to one-tenth of its normal value? You didn't? Well, it's true ... and Birkeland proved it (in one of those math-dense sections you cannot understand) ...

[Tubbythin]

Understood. FYI, I've come to respect you a great deal through our conversations the last few months and I appreciate your candor and fair minded attitude. Please put yourself in my skeptical shoes here for just a second.

First we find that we may be able to double the number of point sources in a galaxy, effectively doubling the amount of ordinary mass in a galaxy. We also have some evidence that we may have also underestimated the number of small stars in a galaxy compared to the number of larger ones. Both of these pieces of relatively new information suggest that we could easily double or triple the amount of normal matter in a galaxy, simply by changing a few of the variables.

"Missing mass" is still a necessity, but then we have evidence that a lot of the newly discovered missing mass is normal matter. For all we know all of the missing mass is contained in ordinary matter.
DRD has answered this pretty well already. All I'd add is that its not just the amount but the distribution of the mass that doesn't agree with the visual mass measurements.


"Missing mass" is a "necessity" for the time being due to limits of our technology, but SUSY theory is still entirely without merit.
This is just odd. You seem to be implying that the case for SUSY rests almost entirely on the existence or otherwise of dark matter. This is simply not the case. The fact that the properties of SUSY particles are such that currently one could well explain the origin of DM stengthens the case for investigating it, not weakens it. Even if DM isnt largely made up of a lightest stable SUSY particle, this doesn't falsify the latter. Its still a fairly simple (relatively speaking), elegant (probably, I'm no expert) solution to a number of "problems" in the Standard Model.


There are hundreds of billions of stars and a galaxy and we may need to double or triple that number just to explain what we've seen so far. That type of "solution' to a "missing mass" problem is also congruent with the presence of additional gamma rays coming from additional suns and planets in the solar systems. We now have a very simple way to explain additional gamma rays, and a lot of that "missing mass" we're looking for. Any sort of Occum's razor argument is going to effectively destroy a "dark matter" solution to a surplus gamma ray problem IMO.
You can proclaim that all you want Michael. But physics is a qunatitative science. If you can't show it numerically you don't have anything.


I really do not see a logical or sound reason to believe that any of the gamma rays seen in Fermi images have anything at all to do with "dark matter". I see lots of evidence to suggest that we grossly underestimate the number of point sources in a given galaxy and I see lots of evidence that know sources of energy (like discharges) are fully capable of explaining what we observe.
Well you haven't shown us any quantitative evidence of the latter.

[Michael Mozina]

Dude, your gross ignorance is showing.

There is ~seven decades of effort, strenuous effort, spent on exactly this.

Only after all such avenues had been investigated, and came up empty, did CDM really come into its own.

How about those two revelations I mentioned? Ooops?

IIRC, one of the first sets of HST observations was aimed at determining if there were sufficient red dwarfs in the halo to account for the known missing mass ... there weren't (and MACHO, OGLE, etc, etc, etc subsequently, and independently, verified this result).

So ultimately a lot of the missing mass turns out to be related to "dust" and the "assumption' related to how many small stars to small stars we can expect to observe.

I guess you really don't comprehend the difference between "empirical physics' and stuff someone just makes up in their head. I guess you have it in your head that our mass estimates for galaxies is "correct", but I just provided you with two papers to demonstrate that this is a false assumption and our mass estimate numbers could be off by several multiples.

[Michael Mozina]

Now we're into repeat mode ...

EITHER you trash GR, because it cannot be demonstrated "in the lab", and insist that astronomers try harder to find Vulcan.

OR you accept that GR is a better theory of gravity (than Newton's) BECAUSE it can do the numbers on the sky, DESPITE the fact that no one can demonstrate it "in the lab"*

Bzzt. False dichotomy fallacy. Minus 5 points for you. Is it true that we use Einstein's theories in GPS systems? I've heard that statement before but I've never actually checked it out.

I accept "GR theory" (the way Einstein taught it) with the constant of gravity set to zero. I'm not into your blunder theory variation that is stuffed with magic because I've never seen gravity do repulsive tricks.

[Tubbythin]

I accept "GR theory" (the way Einstein taught it) with the constant of gravity set to zero.
:jaw-dropp. I assume you mean the cosmological constant.


I'm not into your blunder theory variation that is stuffed with magic because I've never seen gravity do repulsive tricks.
It was only a blunder fine-tuned the constant so to put the universe in an equilibrium that is unstable. There was never any real reason to think the CC was zero, it just looked nicer that way. In fact, when comparing with QM, the big question is more along the lines of "Why is the cosmological constant so small?"

[edd]

Bzzt. False dichotomy fallacy. Minus 5 points for you. Is it true that we use Einstein's theories in GPS systems? I've heard that statement before but I've never actually checked it out.

I accept "GR theory" (the way Einstein taught it) with the constant of gravity set to zero. I'm not into your blunder theory variation that is stuffed with magic because I've never seen gravity do repulsive tricks.

You mean the cosmological constant set to zero.

Anyway, you've never seen gravity do general relativistic tricks, let alone repulsive. It's way outside the ability of a laboratory to test, and yet it is well tested.

[Tubbythin]

Anyway, you've never seen gravity do general relativistic tricks, let alone repulsive. It's way outside the ability of a laboratory to test, and yet it is well tested.

Hmm. Pound-Rebka?

[Michael Mozina]

:jaw-dropp. I assume you mean the cosmological constant.

Ooops. :) It's getting late in the day and evidently I need more coffee. :)

It was only a blunder fine-tuned the constant so to put the universe in an equilibrium that is unstable. There was never any real reason to think the CC was zero, it just looked nicer that way. In fact, when comparing with QM, the big question is more along the lines of "Why is the cosmological constant so small?"

IMO there's still a "cause/effect" issue going on that has absolutely nothing whatsoever to do with "dark energy". Why? Because "dark energy" doesn't do anything to plasma in a lab whereas the EM field does.

[edd]

Hmm. Pound-Rebka?

Fair point.

I don't think Michael's seen it though, and arguably a second hand experiment relayed by verbal means is less reliable than one relayed by photons directly from the experiment, which is what an astronomical observation is.

[Michael Mozina]

You mean the cosmological constant set to zero.

Anyway, you've never seen gravity do general relativistic tricks, let alone repulsive. It's way outside the ability of a laboratory to test, and yet it is well tested.

No it's not. While I actually prefer an 'expansion' process to a static universe, there's no evidence that "gravity" is involved in this repulsive process. There's one obvious macroscopic force of nature that is 39 OOM more powerful than gravity, but it's not "dark energy". :)

[edd]

No it's not. While I actually prefer an 'expansion' process to a static universe, there's no evidence that "gravity" is involved in this repulsive process. There's one obvious macroscopic force of nature that is 39 OOM more powerful than gravity, but it's not "dark energy". :)

Expansion is not repulsion.

That EM is not up to the job is another, and rather tired, matter.

[Reality Check]

You forgot the whole "cause/effect" benefit of "controlled experiments".
...snip...
You can't do that with pure observation, you can't necessarily isolate a "cause".

Actually there is no guarantee that you can isolate a "cause" from controlled experiments either. Some experiments are impossible or too expensive to do. For example what is the 'cause' of cosmic rays and what controlled experiment do you propose to establish it?

Here is a "pure observation": Light from stars have absorption lines in them. Can you isolate a 'cause' for these absorption lines?


It's evidence of "missing mass" or 'unidentified mass'.
...snip...

Just measuring the the mass distribution is evidence of "missing mass". The evidence that the mass is not normal matter is: the three observations of dark matter separated from normal matter: Bullet Cluster (http://chandra.harvard.edu/photo/2006/1e0657/),MACS J0025.4-1222 (http://hubblesite.org/newscenter/archive/releases/2008/32/) and Abell 520 (http://en.wikipedia.org/wiki/Abell_520).


Yes there is. The leap of faith is similar to the UFO scenario. You are assuming that because we cannot identify the object, it must *NECESSARILY* be from another planet. In my analogy, yes, it's currently "unidentified", but it could be (and probably is) from *THIS* planet. You're making a huge assumption to claim that the missing mass is anything other than ordinary matter.
[/qote]
No there is not.

[quote=Michael Mozina;5269489]
Ah, here's where the ridicule begins? What up with that? If you can't beat me via empirical physics, try a personal attack? You must be getting desperate.

It is not a personal attack. Any intelligent person can see that the three observations (empirical physics!) of dark matter separated from normal matter (Bullet Cluster (http://chandra.harvard.edu/photo/2006/1e0657/),MACS J0025.4-1222 (http://hubblesite.org/newscenter/archive/releases/2008/32/) and Abell 520 (http://en.wikipedia.org/wiki/Abell_520)) are overwhelming evidence for dark matter.


Sure but you refused to consider that fact that the missing mass could be ordinary matter. You refused to actually "confirm" any of the properties of your metaphysical brand of "dark matter". You simply "assumed" all of them on an "as needed" basis to fill the gaps of your otherwise failed mass calculation theory. Even when there is evidence presented to you that we may have underestimated the number of stars in galaxies by a large factor, you still *assume* that new and exotic matter is necessary or required. Why?
Because:
Gravitational measurements show that 25% to 30% of the universe is mass.

The measured mass of stars are only about 0.5% of the mass in the Universe.
The measured mass of the intergalactic medium is 3.6% of the mass in the Universe.
I can understand that 0.4% is about 60 times less than 25%?
I can understand that even if astronomers are out by a factor of 2 then 1% is less than 25%?
I can understand that even if astronomers are out by a factor of 10 then 4% is less than 25%?
I can understand that even if astronomers are out by a factor of 50 then 20% is less than 25%?

Can you?

[Michael Mozina]

Fair point.

I don't think Michael's seen it though, and arguably a second hand experiment relayed by verbal means is less reliable than one relayed by photons directly from the experiment, which is what an astronomical observation is.

I really don't grasp why you (lots of astronomers) call these simple observations "experiments". There is no control mechanism in an "observation" and therefore there is no way to determine "cause" in these types of "observations". We observe gamma rays. Period. We aren't controlling them. We aren't controlling the voltages, the amps, the number of "dark matter" particles, or anything of the sort. We therefore have no clue as to "cause" of the gamma rays.

The empirical difference between our positions is that I can physically demonstrate a "cause/effect" relationship between "discharges" and gamma rays. Even still I can't "experiment" with the idea in space. I can "look for evidence" but since I have no control of distant events, and limited technology, there's no cause/effect determination that is possible from this simple "observation" of gamma rays.

[DeiRenDopa]

Now we're into repeat mode ...

EITHER you trash GR, because it cannot be demonstrated "in the lab", and insist that astronomers try harder to find Vulcan.

OR you accept that GR is a better theory of gravity (than Newton's) BECAUSE it can do the numbers on the sky, DESPITE the fact that no one can demonstrate it "in the lab"*Bzzt. False dichotomy fallacy. Minus 5 points for you. Is it true that we use Einstein's theories in GPS systems? I've heard that statement before but I've never actually checked it out.
Dude, the point of this exercise is to see - using historical examples - if your approach works.

GPS etc came many decades after Pound/Rebka, and neither of these - nor any other test of GR - involves creating planets orbiting the Sun "in the lab", in order to observe the perihelia.

Imagine an MM clone writing in the 1920s, 1930s, 1940s, - you get the idea - Pound/Rebka, GPS, artificial satellites, space probes, the HST, etc, etc, etc are all in the far future (if imaginable, credibly, at all).

During this period the MM clone would have written just as you have done, concerning "gravity", controlled experiments "in the lab", a perfectly good alternative explanation that astronomers were not spending time on (Vulcan)*, etc, etc, etc.

I accept "GR theory" (the way Einstein taught it) with the constant of gravity set to zero. I'm not into your blunder theory variation that is stuffed with magic because I've never seen gravity do repulsive tricks.
You don't get to pick and choose ... unless you admit, openly and honestly, that you are being non-scientific (i.e. subjective, idiosyncratic, and inconsistent); gravity with Λ does just as good a job of accounting for 'numbers in the sky' as GR did for the orbit of Mercury.

Ready to make the big admission, MM? That all your posturing amounts to non-science, pure and simple?

* well, that would have been the ignorant claim; the reality, of course, may have been quite different ...

[Michael Mozina]

Actually there is no guarantee that you can isolate a "cause" from controlled experiments either.

I suppose it depends on the experiment but what's the point of having a control mechanism if you aren't trying to isolate cause?

Some experiments are impossible or too expensive to do. For example what is the 'cause' of cosmic rays and what controlled experiment do you propose to establish it?

Well, EM fields have been known to accelerate charged particles to very high speeds, so I'd guess the EM field is responsible for many of them.

Here is a "pure observation": Light from stars have absorption lines in them. Can you isolate a 'cause' for these absorption lines?

Not from the observation itself, but I might be able to do that in controlled experiments here on Earth.

Just measuring the the mass distribution is evidence of "missing mass".

It still tells you *nothing* about it's composition.

The evidence that the mass is not normal matter is: the three observations of dark matter separated from normal matter:

That is not 'evidence that the mass is not normal matter". All that is is 'evidence" that most of your 'missing mass" in likely to be contained inside of solar systems. That's hardly "big news" to a guy that believes in heavy element suns. :)

We're now going around in circles because you refuse to acknowledge that all this lensing data tells us is where this 'missing mass' is located and maybe a little bit about it's composition. If most of that "missing mass" is in the form of "clumps" (suns, planets, moons, comets, asteroids, etc) the matter is not likely to interact with "clumps" in the colliding galaxy. Evidently most of our 'missing mass' follows the infrastructure of the solar systems, not the ISM. That's all your colored diagrams show us. Everything else you said is "imagined". You "imagine" these color represent something they do not. They do not tell us which of the matter is contained in ordinary elements from the periodic table and which are not. They only tell us where our mass estimates are most flawed, and evidently it's not the ISM where we're really off the mark. Like I said, that is hardly news to me personally.

[Michael Mozina]

You don't get to pick and choose ... unless you admit, openly and honestly, that you are being non-scientific (i.e. subjective, idiosyncratic, and inconsistent);

Well, choosing to trust empirical physics is in fact a "subjective" choice I suppose. It is however completely consistent and it is entirely "scientific". I do get to "pick and choose" to have beliefs, or lack of belief based on whether or not an idea can be empirically demonstrated. There's nothing "non-scientific" about empirical physics.

gravity with Λ does just as good a job of accounting for 'numbers in the sky' as GR did for the orbit of Mercury.

Ya, and "gravity" shows up in a lab too DRD. Gravity however does not do any of repulsive tricks in empirical tests.

Ready to make the big admission, MM?

Sure. Care to now make the big admission that you cannot demonstrate that the term "dark matter" is anything other than ordinary matter you can't identify yet? Care to make the big admissions that exotic forms of "dark matter" cannot be shown to emit anything under any circumstance because it's never happened in the whole history of Earth as far as you know?

That all your posturing amounts to non-science, pure and simple?

Your dead inflation deities and dark stuff amounts to non-scientific religion, pure and simple. Like a YEC, you "hope" (and evidently pray) that your beliefs will "one day" be vindicated via empirical physics, even though today you are completely without empirical support of your beliefs. Like YEC only Lambda-CDM and YEC require "faster than light expansion". Pure coincidence?

[DeiRenDopa]

Dude, your gross ignorance is showing.

There is ~seven decades of effort, strenuous effort, spent on exactly this.

Only after all such avenues had been investigated, and came up empty, did CDM really come into its own.How about those two revelations I mentioned? Ooops?
I look forward to your reading your paper on this; until then ...


IIRC, one of the first sets of HST observations was aimed at determining if there were sufficient red dwarfs in the halo to account for the known missing mass ... there weren't (and MACHO, OGLE, etc, etc, etc subsequently, and independently, verified this result).

So ultimately a lot of the missing mass turns out to be related to "dust" and the "assumption' related to how many small stars to small stars we can expect to observe.
Repeating your misunderstandings doesn't magically turn them into physics, MM.

I guess you really don't comprehend the difference between "empirical physics' and stuff someone just makes up in their head.
I understand that the MM approach is subjective, idiosyncratic, and inconsistent ... i.e. that it is not science.

Let's do a test: should you cease posting - here or anywhere on the internet - for an extended period, can you honestly say that anyone (a particular person, or persons) could carry on making the case you are making? If not, then haven't we just demonstrated that your approach is, in fact, subjective, and idiosyncratic?

I guess you have it in your head that our mass estimates for galaxies is "correct", but I just provided you with two papers to demonstrate that this is a false assumption and our mass estimate numbers could be off by several multiples.
Repeating your misunderstandings doesn't magically turn them into physics, MM.

[DeiRenDopa]

Ooops. :)[...]

IMO there's still a "cause/effect" issue going on that has absolutely nothing whatsoever to do with "dark energy". Why? Because "dark energy" doesn't do anything to plasma in a lab whereas the EM field does.
But, as we have seen - over and over and over again - your "O" is subjective, idiosyncratic, and inconsistent.

Got a paper or three in the works, MM? Where you show - using numbers etc - that the EM field (and plasma) will do the trick? If not, why not?

[DeiRenDopa]

Well, choosing to trust empirical physics is in fact a "subjective" choice I suppose. It is however completely consistent and it is entirely "scientific". I do get to "pick and choose" to have beliefs, or lack of belief based on whether or not an idea can be empirically demonstrated. There's nothing "non-scientific" about empirical physics.

[...]

So, is the prominent 500.7 nm emission line, seen in many nebulae, due to nebulium, or [OIII]?

Do neutron stars exist?

Is SgrA* an SMBH?

And so on.

Can you explain, again, please how this works? Specifically, what are the objective, verifiable, consistent rules regarding extrapolation beyond "in the lab" environments?

[Reality Check]

If you want to continue this discussion then it should be in the previous thread where you stated this "missing matter" stuff. (http://forums.randi.org/showthread.php?p=5257138#post5257138)
Maybe you can answer the simple question about colliding blobs that you have been avoidig since 18 July 2009 (108 days and counting).

Alternately I could post the question here but I thnk that counts as cross-posting.

It still tells you *nothing* about it's composition.

It tells you that is is not normal matter.
It tells you that you have to do experiments and observe more to find out what the composition of dark matter actually is.


That is not 'evidence that the mass is not normal matter". All that is is 'evidence" that most of your 'missing mass" in likely to be contained inside of solar systems. That's hardly "big news" to a guy that believes in heavy element suns. :)

You have just claimed that stars are 60 times more massive than astronomers have measured. :eye-poppi
That is about the silliest thing that you have said. I hope that you are joking.

You are still ignorant of the fact that measurement show most of the visible matter in the universe is not in stars (0.4%). It is in the intergalactic medium (3.6%).

You are still ignorant about the fact that the three observations of dark matter separated from normal matter (Bullet Cluster (http://chandra.harvard.edu/photo/2006/1e0657/),MACS J0025.4-1222 (http://hubblesite.org/newscenter/archive/releases/2008/32/) and Abell 520 (http://en.wikipedia.org/wiki/Abell_520)) are about the intergalactic medium (most of the mass in the galactic clusters).


We're now going around in circles because you refuse to acknowledge that all this lensing data tells us is where this 'missing mass' is located and maybe a little bit about it's composition.

The lensing data for non-colliding galactic clusters tells us that there is 'missing matter" located mostly between galaxies. It tells us little (or nothing) about its composition.

But the lensing data for the Bullet Cluster (http://chandra.harvard.edu/photo/2006/1e0657/),MACS J0025.4-1222 (http://hubblesite.org/newscenter/archive/releases/2008/32/) and (maybe) Abell 520 (http://en.wikipedia.org/wiki/Abell_520) tells us that most of the intergalactic medium (and so most of the mass) in those clusters acts differently from normal matter.
This non-normal matter acts as if it interacts weakly with other matter (possibly only electromagnetically). It passes through the normal matter and forms blobs to each side in the observations.
(see this post for the simple question that you hv


If most of that "missing mass" is in the form of "clumps" (suns, planets, moons, comets, asteroids, etc) the matter is not likely to interact with "clumps" in the colliding galaxy.

Still displaying your ignorance:
intergalactic medium not stars,
Colliding galactic clusters not galaxies.


Evidently most of our 'missing mass' follows the infrastructure of the solar systems, not the ISM. That's all your colored diagrams show us.
And yet more ignorance.

Have a look at The Camera that Changed the Universe: Part 4 (http://scienceblogs.com/startswithabang/2009/05/the_camera_that_changed_the_u4.php)
What can you learn from this? Well, other than all sorts of things about the lensed galaxies, you can learn about dark matter! You see, gravitational lensing only cares about mass, and so we can figure out where -- in a cluster like this -- the mass is distributed. The results are breathtaking.
http://scienceblogs.com/startswithabang/upload/2009/05/the_camera_that_changed_the_u4/mass_recon0024_500.jpg
What this shows you is that yes, there are spikes where the individual galaxies are. But the cluster is dominated by this giant spherically-distributed mass that's present everywhere, both where there are galaxies and where there aren't. And that has got to be dark matter.
Emphasis added for those who cannot understand that the diagram shows massive amounts of mass outside of galaxies.

If I remember rightly, the density of the inergalactic medium in this surface density diagran is about 0.1 gm/square cm.

[Michael Mozina]

Maybe you can answer the simple question about colliding blobs that you have been avoidig since 18 July 2009 (108 days and counting).

You're a trip. I have not 'avoided' you on this issue at all, in fact I've been in your collective face about it for years. In all that time not one astronomer has been able to round up even a single gram of this magic matter stuff, and yet you expect me to believe you anyway.

It tells you that is is not normal matter.

It tells you *nothing of the sort*! You simply *assumed* that it is not "normal matter". All you know is that our technologies are limited and you can't "see" all the matter in a galaxy. Big deal. Nothing unusual there.

It tells you that you have to do experiments and observe more to find out what the composition of dark matter actually is.

Well, I 'sort of' agree with you, at least in the sense that it is still relevant and necessary to explain the "missing mass'. Again however there is zero empirical evidence that any of that missing mass is anything other than 'normal matter'.

You have just claimed that stars are 60 times more massive than astronomers have measured. :eye-poppi

Actually no, I said they were more abundant than you realize and most of your "missing mass" tracks with the solar system infrastructure according to the lensing data.

I'm going to skip some of the redundant stuff.

This non-normal matter acts as if it interacts weakly with other matter (possibly only electromagnetically).

Well duh! If two solar systems pass by one another at a couple millions of miles per hour at a couple light years distance, they aren't likely to interact with each other "strongly". In fact they may hardly interact at all. Again, let me state emphatically that you know absolutely nothing at all about the composition of that unknown material based on this information..

It passes through the normal matter and forms blobs to each side in the observations.

With enough velocity and momentum, normal matter "passes through" normal matter too. So what? Solar systems are typically separated by light years. In in a high speed galaxy "collision" it's highly unlikely that the solar system infrastructures will directly collide. Even if a few stars or planets actually do actually slam into one another, the vast majority of objects in the solar systems will not collide but pass right through to the other side. In no way is that behavior "mystical" or "magical" or even "unexpected". So what? Ordinary matter would be expected to "pass through" any sort of 'collision' process in "vast quantities", whereas particles in the ISM might actually "collide".

That is entirely consistent with the core stellar infrastructure passing right through the other galaxy. Based on the distances between stars, that is hardly surprising. A "direct hit" between two stars is an astronomically low probability.

We're going around in circles now because you absolutely refuse to acknowledge that the reason we cannot 'see' this material is due to the limits of our technology. The reason we can't tell what it's made of is due to the limits of our technology. You can't tell what type of matter is 'missing', and you certainly cannot tell what it's made of from millions if not billions of light years away. You are simply "assuming" that this is some sort of exotic material. That is a pure act of faith on your part. You don't know that. You *assumed* that. You don't know that our galaxy mass estimates are anywhere near accurate so you really have no idea how much normal material is present, let alone be sure if you need anything other than normal material.

I showed you evidence that the universe is much brighter than we expected and galaxies are likely to have far more smaller stars per large star than we used to believe. The net result is that we may easily be able to double or triple the amount of normal matter in a given galaxy (like your collision galaxies), demonstrating that a lot of that 'dark matter' is composed "normal matter" despite your wild claims to the contrary.

An unidentified flying objects isn't *NECESSARILY* from another planet. Likewise "missing mass" isn't "SUSY material" (with all the ad hoc properties you assigned to it all willy nilly).

[Michael Mozina]

What exactly were you expecting to "see" anyway?

Considering the distances involved with solar systems, they will most likely pass through one another. Likewise, even the distance between particles in the ISM could be substantial and not even individual atoms/ions in the ISM would necessarily "collide". Even much of the the material in the ISM could 'pass through' ordinary matter. I fail to understand exactly what it is about this image that you find surprising in terms of what to expect from normal matter (like that dust and doubling of point sources).

[DeiRenDopa]

[...]
It tells you that is is not normal matter.
It tells you *nothing of the sort*! You simply *assumed* that it is not "normal matter". All you know is that our technologies are limited and you can't "see" all the matter in a galaxy. Big deal. Nothing unusual there.
Are you sure?

Can you describe a distribution of normal matter, in a rich cluster of galaxies, which is consistent with all relevant astronomical observations?

An order of magnitude "consistent with" will do (for now).

If you can't, what objective, independently verifiable basis is there for your claim?


It tells you that you have to do experiments and observe more to find out what the composition of dark matter actually is.
Well, I 'sort of' agree with you, at least in the sense that it is still relevant and necessary to explain the "missing mass'. Again however there is zero empirical evidence that any of that missing mass is anything other than 'normal matter'.
Only in the sense that astronomical observations do not constitute "empirical evidence".

If you discount such observations, why do you bother writing posts about astronomy?

[...]
It passes through the normal matter and forms blobs to each side in the observations.
With enough velocity and momentum, normal matter "passes through" normal matter too. So what? Solar systems are typically separated by light years. In in a high speed galaxy "collision" it's highly unlikely that the solar system infrastructures will directly collide. Even if a few stars or planets actually do actually slam into one another, the vast majority of objects in the solar systems will not collide but pass right through to the other side. In no way is that behavior "mystical" or "magical" or even "unexpected". So what? Ordinary matter would be expected to "pass through" any sort of 'collision' process in "vast quantities", whereas particles in the ISM might actually "collide".

That is entirely consistent with the core stellar infrastructure passing right through the other galaxy. Based on the distances between stars, that is hardly surprising. A "direct hit" between two stars is an astronomically low probability.
What happened to all the light from the stars which are the primaries of all the solar systems?

Where did all the mass which stars that have passed through the red giant-PNe stage of evolution shed go?

And so on.

We're going around in circles now because you absolutely refuse to acknowledge that the reason we cannot 'see' this material is due to the limits of our technology. The reason we can't tell what it's made of is due to the limits of our technology.
Actually, the main reason why we keep going on this merry-go-round is that you absolutely refuse to acknowledge that astronomers have many independent techniques for estimating the distribution and composition of ordinary (normal) matter in the IGM of rich clusters.

Where does this willful ignorance come from?

You can't tell what type of matter is 'missing', and you certainly cannot tell what it's made of from millions if not billions of light years away.
Of course he can ... you just don't want to listen.

You are simply "assuming" that this is some sort of exotic material. That is a pure act of faith on your part. You don't know that. You *assumed* that. You don't know that our galaxy mass estimates are anywhere near accurate
Of course he does ... you just don't want to listen.

so you really have no idea how much normal material is present, let alone be sure if you need anything other than normal material.

I showed you evidence that the universe is much brighter than we expected and galaxies are likely have far more smaller stars per large star than we used to believe.
You did not.

You cited two PRs, and when confronted with copies of the papers*, refused to read them.

Further, you have refused to show - you know, with numbers and equations - how the findings reported in those papers affect determination of the distribution of mass within a normal spiral galaxy (HINT: the need for a DM halo is just as strong with or without these papers' results).

You have also refused to cite papers - of which there are dozens, possibly hundreds - which report findings different from (at odds with) these two.

And so on.

IOW, the case you continue to present continues to be subjective, deliberately misleading, and inconsistent.

The net result is that we may easily be able to double or triple the amount of normal matter in a given galaxy (like your collision galaxies), demonstrating that a lot of that 'dark matter' is composed "normal matter" despite your wild claims to the contrary. [...](bold added)

"We" are waiting for you to do exactly that.

How's the paper coming along, MM?

* preprints actually

[Michael Mozina]

Are you sure?

Positive. You and I don't have the technology necessary to see 'everything' in a galaxy. We subjectively 'interpret' a whole lot based on a limited set of data.

Can you describe a distribution of normal matter, in a rich cluster of galaxies, which is consistent with all relevant astronomical observations?

Nope, and neither can you which is why you're stuffing the gaps with "dark matter".

If you can't, what objective, independently verifiable basis is there for your claim?

My claim of what? All I know is we have relatively primitive technology that limits our capabilities. We can't account for all the mass in a galaxy based on our current mass estimates. So what? None of these facts necessitates new and exotic "made up" matter with ad hoc properties galore. I'd say it's time to "scrap" the mass estimation techniques and start over again.

If you discount such observations, why do you bother writing posts about astronomy?

You're putting a very odd 'spin' on statements (again). I don't discount the observations of "missing mass". I "discount" your belief that you already know/knew exactly how much "normal" matter exists in any given galaxy in any of those lensing studies. All you can do here is use "flawed" mass estimation techniques, and then compare it to the lensing data "measurements", and thereby "test" your mass estimation techniques. They *FAILED MISERABLY*. Let that mass estimation technique die a natural death and try again.

If you *insist* on sticking with your old and "failed" theories of "normal mass" estimation, and want to call the difference "dark matter", ok. Don't however turn around and pretend your failed mass estimation techniques were valid all along and the difference is made up of "exotic matter" with ad hoc properties galore.

[Michael Mozina]

Because:
Gravitational measurements show that 25% to 30% of the universe is mass.

What pray tell is the rest made of? Please resist the need to stuff the gaps of your ignorance with useless terms like magic energy.

The measured mass of stars are only about 0.5% of the mass in the Universe.

You didn't "measure" the mass of the stars, you "estimated" the mass of the stars. Those estimate were based upon a whole host of assumptions like the amount of light absorbed by dust, etc, all of which have now been shown to be "questionable" at best.

The measured mass of the intergalactic medium is 3.6% of the mass in the Universe.

Again, this too is 'assumed' and/or "estimated", it is not "measured".

I can understand that 0.4% is about 60 times less than 25%?

I can understand that when a mass estimation technique is that far off, it's time to give it a proper scientific burial and call it "falsified" once and for all. Evidently we need some new mass estimation techniques that jive with the lensing data?

All the rest of your "assumption" are evidently based on the false belief that we have accurately "measured" the amount of mass in a galaxy, when in fact we never did. We "estimated' that mass, and clearly we did a pitiful job that in no way agrees with the lensing data. One of the two "techniques" for "measuring" the mass of a galaxy is wrong, and one is correct. The lensing data is most likely to be "correct". The "estimation' process is most likely to be incorrect because it is based on far many more assumptions than the lensing data.

All this information tells us ultimately is that the mass estimation techniques we use today are nearly useless at determining that actual amount of mass in a galaxy. Period.

It does *not* tells us that *BOTH* methods of determining mass are correct as you are trying to claim! That is simply an "outrageous" claim IMO.

[Michael Mozina]

They only tell us where our mass estimates are most flawed, and evidently it's not the ISM where we're really off the mark. Like I said, that is hardly news to me personally.

The more I think about it, the more I think this statement is less than accurate. I really don't know how much of the ISM is likely to simply 'pass through' the ISM of the other galaxy. A lot will depend on the composition and speed of the ISM, but even the majority of that material could in fact 'pass trough' the 'collision' process.

The more I think about it, the images don't even actually tell me anything more than most of the materials passes through the collision process. Period. A lot of that mass could be in the ISM or in bodies in the solar system infrastructures, but the lensing data does seem to suggest that "collisions" are more of a 'pass through' process when the momentum and angular directional components are favorable.

[DeiRenDopa]

Are you sure?Positive. You and I don't have the technology necessary to see 'everything' in a galaxy. We subjectively 'interpret' a whole lot based on a limited set of data.
Sigh.

Doin' the Gish Gallop again are we MM?

"All you know is that our technologies are limited and you can't "see" all the matter in a galaxy" - that's your claim.

Now, what do you understand by gravitational lensing, MM? After all, did you not say you were a card-carrying member of the Einstein GR club?

Other readers: yeah, I know, we've been here, done this, got a dozen t-shirts ... if MM keeps up with this blatant dishonesty, I'm done ...


Can you describe a distribution of normal matter, in a rich cluster of galaxies, which is consistent with all relevant astronomical observations?

Nope, and neither can you which is why you're stuffing the gaps with "dark matter".
Thank you.

But I thought you declared astronomy not science, seeing as you can't test anything much "in the lab"; you did do this, didn't you?

Yet another demonstration of your subjective, inconsistent worldview?

Where's the science MM?

If you can't, what objective, independently verifiable basis is there for your claim?
My claim of what?
That all you need is normal matter (no CDM required).

All I know is we have relatively primitive technology that limits our capabilities. We can't account for all the mass in a galaxy based on our current mass estimates. So what? None of these facts necessitates new and exotic "made up" matter with ad hoc properties galore. I'd say it's time to "scrap" the mass estimation techniques and start over again.
And I'd say it's time for you to stop being willfully ignorant, and go learn some astronomy.

Wait ... you ignored this suggestion, what, a dozen times or more; OK, forget it.

If you discount such observations, why do you bother writing posts about astronomy?
You're putting a very odd 'spin' on statements (again). I don't discount the observations of "missing mass". I "discount" your belief that you already know/knew exactly how much "normal" matter exists in any given galaxy in any of those lensing studies. All you can do here is use "flawed" mass estimation techniques, and then compare it to the lensing data "measurements", and thereby "test" your mass estimation techniques. They *FAILED MISERABLY*. Let that mass estimation technique die a natural death and try again.
Dude, no one has tested gravitational lensing, by ~sol mass objects (much less ~trillion sol mass objects), "in the lab", so how do you know anything?

Remind me again, please, what are the allowable limits of extrapolation (of theories such as GR, from "in the lab" tests)?

If you *insist* on sticking with your old and "failed" theories of "normal mass" estimation, and want to call the difference "dark matter", ok. Don't however turn around and pretend your failed mass estimation techniques were valid all along and the difference is made up of "exotic matter" with ad hoc properties galore.
You could care less about what I - or anyone else - does, wrt astrophysical analyses ... you are trying to show - using your subjective, idiosyncratic, inconsistent approach - that all relevant astronomical observations can be accounted for - quantitatively - with distributions of normal (baryonic) matter.

So far, you have failed - miserably - to do so.

[Michael Mozina]

Now, what do you understand by gravitational lensing, MM? After all, did you not say you were a card-carrying member of the Einstein GR club?

I know enough about it to believe that it works as advertised in the sense that matter will cause a curvature of spacetime that can act as a lens in some cases. I'll even go so far as to let you use that method to "test" your "galaxy mass estimates". Oh look, according to the lensing data, your mass estimate technique failed miserably. Now what?

[DeiRenDopa]

Now, what do you understand by gravitational lensing, MM? After all, did you not say you were a card-carrying member of the Einstein GR club?I know enough about it to believe that it works as advertised in the sense that matter will cause a curvature of spacetime that can act as a lens in some cases. I'll even go so far as to let you use that method to "test" your "galaxy mass estimates". Oh look, according to the lensing data, your mass estimate technique failed miserably. Now what?
Huh?

Lensing observations tell you what the mass of the lens is (and, in some cases, its distribution).

These observations, combined with many others (of several different kinds), are consistent with the existence of a great deal of 'non-baryonic' (not normal), cold mass. The distribution of this kind of mass is consistent with it having a very low electromagnetic cross-section, i.e. behaving as cold, dark, collisionless, mass.

And, let's not forget, consistent ... quantitatively.

Which brings us right back to the paper you're working on ... showing that the amount of, and distribution of, normal matter (in rich clusters, galaxies of many kinds, etc, etc, etc) required to be consistent with the lensing observations is such-and-such, AND showing that this amount, and distribution, is consistent with ALL relevant other astronomical observations ...

How's that paper coming on, MM?

[Reality Check]

You're a trip. I have not 'avoided' you on this issue at all, in fact I've been in your collective face about it for years. In all that time not one astronomer has been able to round up even a single gram of this magic matter stuff, and yet you expect me to believe you anyway.

I will post it here so everyone can see the simple question that you have been avoiding for 3 months.


It tells you *nothing of the sort*! You simply *assumed* that it is not "normal matter". All you know is that our technologies are limited and you can't "see" all the matter in a galaxy. Big deal. Nothing unusual there.

The assuption is that normal matter acts normally. The IGM interacts gravitationally and electromagnetically. The other stuff in the colliding galaxic clusters does not interact electromagnetically. That is not normal


Well, I 'sort of' agree with you, at least in the sense that it is still relevant and necessary to explain the "missing mass'. Again however there is zero empirical evidence that any of that missing mass is anything other than 'normal matter'.

There is no missing mass. Gravitational lensing has given us good maps of the mass distruction in galactic clusters. The colliding galactic clusters have separated the IGM from the dark matter and shows that dark matter interacts weakly or not al all with normal matter.

Actually no, I said they were more abundant than you realize and most of your "missing mass" tracks with the solar system infrastructure according to the lensing data.

What lensing data?

The lensing data that I have supplied to you is about galactic clusters.It shows that most of the mass in a galactic cluster is
Not in the galaxies.
Not in the intergalactic medium.

Well duh! If two solar systems pass by one another at a couple millions of miles per hour at a couple light years distance, they aren't likely to interact with each other "strongly". In fact they may hardly interact at all. Again, let me state emphatically that you know absolutely nothing at all about the composition of that unknown material based on this information..

Well duh! ou ignorance is astounding.
Astronomers know this. They know that when galxies collide the solar systems in themn do not collide and do not interact "strongly".
But one more time:
Let me state emphatically: The observations are of the colliding intergalactic medium in colliding galactic clusters.
Is that loud enough for you?
Can you read that?
Do you understand that the observations are nothing to do with solar systems?

[Reality Check]

First asked 18 July 2009
Here is the question:

A is a big blob of gas.
B is a bib blob of gas.
Blob A hits blob A.

If the gas is all the same stuff then the result will be another blob of gas.
It is probable that some of the gas will not not collide. In that case there will be blobs of gas to each side. The size of these outlying blobs will reflect the amount of gas that did not collide. See the point below about why insignificant amounts of normal (baryonic) matter will not collide.
If the gas is a mixture of two kinds of gas , one of which interacts weakly with the other, then the result will be 3 blobs since the weakly interacting gas passes through the other gas.
The size of these outlying blobs will reflect the amount of gas that did not collide plus the amount of weakly interacting gas.

We see 3 blobs.
The outlying blobs contain most of the matter in the bolbs A and B.
Thus the gas is made of two kinds of gas, one of which interacts weakly with the other.
Any problems with this analysis with what is going on with the majority of the matter in the Bullet Cluster (http://chandra.harvard.edu/photo/2006/1e0657/) and MACS J0025.4-1222 (http://hubblesite.org/newscenter/archive/releases/2008/32/) (and even Abell 520 (http://en.wikipedia.org/wiki/Abell_520))?

Remember that astronomers can calculate the probability of atoms in the ICM colliding as they travel millions of light years through each cluster. I do not know the exact number but expect it to be high (an atom travels millions of light years through a medium containing about 1 atom per cubic meter - you do the math!).
Thus the amount of gas that did not collide is tiny. The outlying blobs are thus mostly weakly interacting gas, i.e. particles that collided but did not interact strongly.

If you cannot find any problems then you agree that these three observations are evidence that there is matter that does not interact like baryonic matter. This we call nonbaryonic matter.

[Reality Check]

What pray tell is the rest made of? Please resist the need to stuff the gaps of your ignorance with useless terms like magic energy.

The non-magical dark energy (http://en.wikipedia.org/wiki/Dark_energy).


You didn't "measure" the mass of the stars, you "estimated" the mass of the stars. Those estimate were based upon a whole host of assumptions like the amount of light absorbed by dust, etc, all of which have now been shown to be "questionable" at best.

That is right. The masses of stars are estimated from measurements.
Your ignorance is showing again. You obviously did not read the papers or the comments of more knowledgeable posters (unlike you or me).
These papers are about making the estimates more accurate. The question is whether the mass in galaxies is out by a factor of 60 as you claim (to account for the measured/estimated mass).



Again, this too is 'assumed' and/or "estimated", it is not "measured".

Right again - The amount of IGM is eastimated from measurements.


I can understand that when a mass estimation technique is that far off, it's time to give it a proper scientific burial and call it "falsified" once and for all. Evidently we need some new mass estimation techniques that jive with the lensing data?

The mass estimation techniques (you know the ones that agree on the mass) are not "that far off". They are certainly not a factor of 60 off. If you have evidence of this then present it. All you have presented is a couple of news articles that imply a small effect, i.e. off by 20% (a factor of 1.2!) and off by some factor in specfic types of galaxies.


All the rest of your "assumption" are evidently based on the false belief that we have accurately "measured" the amount of mass in a galaxy, when in fact we never did. We "estimated' that mass, and clearly we did a pitiful job that in no way agrees with the lensing data. One of the two "techniques" for "measuring" the mass of a galaxy is wrong, and one is correct. The lensing data is most likely to be "correct". The "estimation' process is most likely to be incorrect because it is based on far many more assumptions than the lensing data.

All this information tells us ultimately is that the mass estimation techniques we use today are nearly useless at determining that actual amount of mass in a galaxy. Period.

It does *not* tells us that *BOTH* methods of determining mass are correct as you are trying to claim! That is simply an "outrageous" claim IMO.
All the rest of your post is evidently based on the false belief that normal matter does not interact strongly electromagnetically with normal matter.

The observations of the Bullet Cluster (http://chandra.harvard.edu/photo/2006/1e0657/), MACS J0025.4-1222 (http://hubblesite.org/newscenter/archive/releases/2008/32/) and (maybe) Abell 520 (http://en.wikipedia.org/wiki/Abell_520) tell us that *BOTH* gravitational lensing and the mass estimation techniques are in agreement.

N.B. Once more: We are talkiing about the lensing data for galactic clusters where most of the mass is in the IGM - not the galaxies.

[Reality Check]

Have a look at The Camera that Changed the Universe: Part 4 (http://scienceblogs.com/startswithabang/2009/05/the_camera_that_changed_the_u4.php)

Emphasis added for those who cannot understand that the diagram shows massive amounts of mass outside of galaxies.

If I remember rightly, the density of the inergalactic medium in this surface density diagran is about 0.1 gm/square cm.
A correction:
The intracluster medium (http://en.wikipedia.org/wiki/Intracluster_medium) (or intergalactic medium):
Although the ICM on the whole contains the bulk of a cluster's baryons, it is not very dense, with typical values of 10-3 particles per cubic centimeter. The mean free path (http://forums.randi.org/wiki/Mean_free_path) of the particles is roughly 1016 m, or about one lightyear.
This is roughly 1 x 10^-21 grams in a cubic meter (1000 H atoms). If we take the depth of the galactic cluster 0024+1624 to be 800,000 light years (which is probably on the generous side) that gives a surface mass density of around 0.001 g/square cm.

The background mass in the diagram has a minimum of 0.3 g/square cm.
I wonder where the extra mass comes from?

[sol invictus]

I know enough about it to believe that it works as advertised in the sense that matter will cause a curvature of spacetime that can act as a lens in some cases. I'll even go so far as to let you use that method to "test" your "galaxy mass estimates". Oh look, according to the lensing data, your mass estimate technique failed miserably. Now what?

Now what? Now we know there's a lot of gravitational mass in and around galaxies that doesn't emit or absorb much EM radiation. Oh look, and that also agrees with the many other techniques the measure or depend on the same quantity (like rotation curves, the power spectrum of galaxies, the CMB, structure formation simulations, etc. etc.).

How, exactly, is that a "failure"?

[DSo]

Science – We have looked up in the sky and see an interesting phenomena. We have estimated the mass of galaxies by multiple methods. We believe we have fairly tight constraints on the amount of “normal” mass in the galaxies. Yet the mass we estimate is only a fraction of that required to explain things like galactic rotation curves. Therefore we postulate that a, to now poorly understood, entity we’ll call Dark Matter also exists. This matter is not detectible by our conventional means of detecting matter. Here is a mathematical model of Dark Matter. Hey look at that! Based on the model for Dark Matter another phenomena can be explained, namely this background of gamma ray noise emitted from the central portion of our galaxy. We know of no explanation using normal matter that better explains the properties of these gamma rays.

Michael Mozina – You’ve just made Dark Matter up in your head, therefore I don’t believe it.

Science – Say again Michael?




I can understand that when a mass estimation technique is that far off, it's time to give it a proper scientific burial and call it "falsified" once and for all. Evidently we need some new mass estimation techniques that jive with the lensing data?

All the rest of your "assumption" are evidently based on the false belief that we have accurately "measured" the amount of mass in a galaxy, when in fact we never did. We "estimated' that mass, and clearly we did a pitiful job that in no way agrees with the lensing data. One of the two "techniques" for "measuring" the mass of a galaxy is wrong, and one is correct. The lensing data is most likely to be "correct". The "estimation' process is most likely to be incorrect because it is based on far many more assumptions than the lensing data.

All this information tells us ultimately is that the mass estimation techniques we use today are nearly useless at determining that actual amount of mass in a galaxy. Period.


Science – On the contrary Michael, most experts in the field agree that we have estimated the amount of normal matter in the galaxies to a relatively small band of estimates. Multiple lines of independent evidence are pointing in the same direction. This range of estimates does not come close to explaining the phenomena we observed. Thus we have a working hypothesis that a poorly understood entity we’ll call Dark Matter exists. The evidence in favor of DM is strong enough that a number of people are devoting large parts, if not all of their careers to the study of this subject.

MM – You folks are obviously wrong! If you belive that then I have some ocean front property in Arizona to sell you!

Science – OK Micheal, we are willing to listen. Do you have an explanation for all these phenomena that is better and simpler than DarkMatter?

MM – You bet I do!

Science – OK, what is it? Show us the evidence and the numbers.

MM – Numbers! I don’t need any freakin’ numbers! Sheeeesh …


DSo – speaking as a curious layman in all of this … I wonder who I should believe?

[Reality Check]

This is almost off topic but since dark energy has been mentioned in this thread, I will point out the "Starts With a Bang" blog is blogging on dark energy starting today with Dark Energy: Hard to Kill (Part 1) (http://scienceblogs.com/startswithabang/2009/11/dark_energy_hard_to_kill_part.php).

Hopefully he will cover one of the better bits of evidence for dark matter and energy:

Scientists use the WMAP data to measure that the universe is spatially flat to within 2% (http://en.wikipedia.org/wiki/Shape_of_the_Universe) (previously the uncertainty was 15%).
Scientists measure the amount of visible mass & energy in the universe.
The result is that 96% of the mass & energy in the universe is missing. This is missing stuff is labeled dark matter and dark energy.
Gravitational lensing data then gives an estimate for the amount of dark matter.
Observations of Type Ia supernovae give an estimate for the amount of dark energy.
The results are that the percentage of mass & energy in the universe from various sources are:

0.4% from stars.
3.6% from the intra-cluster medium (ICM).
23% from dark matter (+/- 3%).
73% from dark energy (+/- 3%).

I do not know what the uncertainties are in the estimates for stars and ICM are.

[Michael Mozina]

Now what?

Ya. Essentially you falsified one "guestimation" of normal matter with two different measurements that evidently both demonstrate the "guestimate" of mass in a galaxy is way off. We also have evidence that dust absorbs/deflects a lot more light than we realized and a lot of that "missing mass" can easily be "explained" by ordinary matter.

Now we know there's a lot of gravitational mass in and around galaxies that doesn't emit or absorb much EM radiation.

Except of course you folks turn right around and tell me it burps out gamma rays on command? This "dark matter" seem to do magic light tricks and still it's 'dark'? What's up with that? Now mind you it *never* does it's gamma ray magic here on Earth or anywhere in the solar system, just "somewhere out there" where we can't see it happen. How bloody inconvenient.

Oh look, and that also agrees with the many other techniques the measure or depend on the same quantity (like rotation curves, the power spectrum of galaxies, the CMB, structure formation simulations, etc. etc.).

So essentially you demonstrated two different ways (lensing and rotation curves) that the "guestimate" of the amount of normal material in a galaxy is "way" off.

We also have some recent ideas as to why that might be, including all that "dust" that blocked all that extra light and caused us to underestimate the number of point sources in a galaxy. Now don't you figure it's about time to toss your previous mass estimates into the trash can and try again?

How, exactly, is that a "failure"?

The "failure" is in your emotional attachment to the "guestimate" and to the belief that 'missing mass' = "exotic particle that does anything I say". Just admit that your previous mass estimates are falsified and try recalculating the normal matter in a galaxy in a way that is more consistent with what we've learned over the last few years via lensing data and rotation curves.

I *LOVE* how you expect me to ignore the fact that the sun and the planets emit gamma rays due to "electrical discharges", but you expect me to also buy this invisible, gamma burping, magic "dark" (but emits gamma rays on command) matter theory. Come on. The believability factor is making "modern astronomy" about as believable as astrology these days. 96% of your theory (and math) is evidently completely useless on Earth. You can't get a "dark matter" thingamabob to emit a single gamma ray on Earth or anywhere in the solar system and you ignore the single most obvious light source in the universe.

[Michael Mozina]

Huh?

"Huh?" right back at you. You've essentially falsified your "normal" mass 'guestimates' twice now and yet you refuse to alter your mass guestimates, even in the face of recent evidence to explain *WHY* you keep blowing the mass estimates! It's like a Monty Python skit - "Tis only a scratch....come back and fight you coward....".

Lensing observations tell you what the mass of the lens is (and, in some cases, its distribution).

These observations, combined with many others (of several different kinds), are consistent with the existence of a great deal of 'non-baryonic' (not normal), cold mass.

BaLOOOOOOOOOOOOOOOny!

It's only evidence that our "normal matter" estimates of point sources (those pesky little stars) are grossly off the mark. It's time to simply scrap your estimates of 'normal' matter and come up with better estimates of "normal matter" because "normal matter" emits light that evidently "normal matter" then absorbs in greater amounts than we first realized.

You're like the individual looking at an unidentified flying objects that immediately makes the wild ass claim that 'it's *definitely* (without any doubt at all) from another planet I tell you!". Balooooooooony.

The distribution of this kind of mass is consistent with it having a very low electromagnetic cross-section, i.e. behaving as cold, dark, collisionless, mass.

How exactly did it "annihilate" again to give us all the pretty bright gamma lights in the sky? How come we never see it happen anywhere on Earth, or anywhere inside this solar system? How come it only happens "out there somewhere" where I conveniently can't reach in my human lifetime? How many of these "wild faith" doctrines do I have to swallow hook line and sinker to be a part of the "dark" astronomy cult?

And, let's not forget, consistent ... quantitatively.

Ya, let's forget all about "qualitatively" verifying anything because you haven't got squat in terms of empirical physics. "Quantitatively" you want me to believe you've accurately counted how many invisible matter faeries fit on the head of pin with "high precision" (with the error bars!) no less. :) Give me a break.

Which brings us right back to the paper you're working on ... showing that the amount of, and distribution of, normal matter (in rich clusters, galaxies of many kinds, etc, etc, etc) required to be consistent with the lensing observations is such-and-such, AND showing that this amount, and distribution, is consistent with ALL relevant other astronomical observations ...

I thought you guys and gals are the "professionals"? Can't you take a break from that dark religion thing of yours to whip something up, or are you so infatuated with the "Dark" thingies that you've dreamed up on paper to try another (empirical) approach?

How's that paper coming on, MM?

That would be on hold while I'm earning a living doing something constructive that I can actually sell on the open market. If you "astronomers" had to live on the consumer products that you could sell on the open market based on "dark energy", "inflation", and "dark matter", you'd starve to death, or be sued for false advertising. How about publishing a paper involving something that *is* known to emit gamma rays like "electrical discharges"? Oh ya, I forgot, that's your arch enemy, your version of the devil in your religion. You folks will do anything and everything to avoid the dreaded "EU theory" in all it's evil guises. :)

[Michael Mozina]

The non-magical dark energy (http://en.wikipedia.org/wiki/Dark_energy).

Yet if I blatantly pilfer your math, you can't tell the empirical difference between 'magic energy' and 'dark energy' and you can't make either one of them show up here on Earth. :)

Now the one macroscopic force of nature that *IS* known to accelerate matter is the electromagnetic field, but again that's the one forbidden topic of astronomy. And that my friends is how we end up with magic, er "dark energy" (complete with nifty math formula stuffed into a blunder theory).

That is right. The masses of stars are estimated from measurements.

Those "measurements" were fine, but your "assumptions" about how much light was being absorbed and deflected was way off evidently.

Your ignorance is showing again. You obviously did not read the papers or the comments of more knowledgeable posters (unlike you or me).
These papers are about making the estimates more accurate.

So how about making your mass estimates "more accurate" and at least double the point sources in a galaxy? Hell, you've got *tons* of missing mass to explain, so you can liberally spread it around.

The question is whether the mass in galaxies is out by a factor of 60 as you claim (to account for the measured/estimated mass).

Unless you can show me some direct evidence of exotic matter the only matter I'm aware of resides in "standard" particle physics theory and the periodic table. If you make a wild claim about exotic matter, I'll expect pretty darn good evidence to substantiate that claim *BEFORE* you start pointing at that sky and claiming magic, er "dark" something or other did it.

[Michael Mozina]

Science – We have looked up in the sky and see an interesting phenomena.

Like when "discharges" emit "gamma rays"? :)

We have estimated the mass of galaxies by multiple methods.

Ok. We have the "lensing method" (I've got no problem with that one). We've go the "rotation" method and that one seems to jive pretty well with the lensing data. Then we have the "wild guessing" method related to how much "normal matter' resides in a galaxy. That one doesn't jive with the other two methods. Maybe it needs replaced?

We believe we have fairly tight constraints on the amount of “normal” mass in the galaxies.

Why? Two methods don't jive with the third and the third one is *FILLED* with all sorts of 'assumptions' that we already know to be suspect.

Yet the mass we estimate is only a fraction of that required to explain things like galactic rotation curves.

So it's broken. Fix it.

Therefore we postulate that a, to now poorly understood, entity we’ll call Dark Matter also exists.

"Missing mass", or "mass we cannot account for" is not automatically composed of "exotic matter". How did we get from "poorly understood" to suddenly being sure it emits gamma rays again?

This matter is not detectible by our conventional means of detecting matter.

None of the matter is "directly" detectable by our conventional means of detection, which is why we have to indirectly detect it by various means (like lensing). We can't "detect' individual stars in a galaxy or begin to count them. We "estimate" them based on a whole series of debatable assumptions.

Here is a mathematical model of Dark Matter. Hey look at that! Based on the model for Dark Matter another phenomena can be explained, namely this background of gamma ray noise emitted from the central portion of our galaxy.

Wait a minute. First it's "poorly understood" and now you know it emits gamma rays too? How did we go from 'poorly understood' to "making up" properties on the fly?

We know of no explanation using normal matter that better explains the properties of these gamma rays.

That's just silly IMO. Of course we do. We know of a at least a half dozen bodies inside this specific solar system that emit gamma rays and we know they are related to "discharges". There is a very simple explanation, but unfortunately it involves that dreaded evil word - "electricity".

You have absolutely no way to know exactly how much "normal matter" there is inside any galaxy that is millions if not billions of light years from Earth. The very best you might hope to do is "estimate" that number, and two other methods demonstrate that one of the other methods is wrong. Instead of fixing the one that's broken, you've started piling on "ad hoc properties", and even more things you cannot empirically demonstrate in a lab. The whole thing is purely goofy at this point. It's clear that there is more blocking of light going on than we realized, and it's clear that it has a greater impact on the number of point sources in a galaxy than we realized.

The mystery here is how you went from "poorly understood" to having 'great confidence' in the belief that it emits gamma rays.

[Michael Mozina]

I will post it here so everyone can see the simple question that you have been avoiding for 3 months.

It's not that I have avoided your question, you have simply avoided my answer.

The assuption is that normal matter acts normally. The IGM interacts gravitationally and electromagnetically. The other stuff in the colliding galaxic clusters does not interact electromagnetically. That is not normal

Pure gibberish IMO. All you know is you cannot account for all the matter. That's hardly surprising since you've been underestimating by the number of small stars in the galaxy and the number of point sources in a galaxy by substantial amounts.

There is no missing mass. Gravitational lensing has given us good maps of the mass distruction in galactic clusters.

Then there's no "dark matter" either because it's been "seen" in the lensing data. You simply blew your "baryonic mass" estimates in a big way.

The colliding galactic clusters have separated the IGM from the dark matter and shows that dark matter interacts weakly or not al all with normal matter.

Gah. You're still ignoring the obvious. The things that "separated" were the "baryonic matter" that didn't collide and the "baryonic matter" that did. There no separation of "bayonic" and "non bayronic" matter in that image. That is completely made up in your head. Some of that baryonic matter you can account for, but the vast majority of it you cannot.

I'm not going to let you simply "make up" stuff regarding that lensing data. The fact that matter is present creates the lensing effect, but that lensing effect can be caused by *ANY* form of matter, including "normal matter". You're the one making the extraordinary claim that somehow it can only be "exotic gamma ray emitting matter" and you can't produce that same event once here on Earth. See a problem with your logic?

There is no way in hell that the lensing data can tell you what that material is made of. Any form of matter will do in terms of bending light.

It's *way* more likely you simply blew the baryonic mass estimates, both in terms of the composition and density of the ISM/IGM and the number of stars in a galaxy. That "dark matter" isn't necessarily "exotic matter" anymore than "unidentified flying objects" are *necessarily* from another planet. You're *leaping* to *wild and speculative* conclusions based on evidence that doesn't ultimately support your claim.

[Reality Check]

It's not that I have avoided your question, you have simply avoided my answer.

I have never noticed any answer. Can you give a link to the post where you state that when 2 blobs of gas made of normal matter collide, most of the matter passes through the blobs without interacting (thus forming 3 blobs)?


Pure gibberish IMO. All you know is you cannot account for all the matter. That's hardly surprising since you've been underestimating by the number of small stars in the galaxy and the number of point sources in a galaxy by substantial amounts.

All I know is that you have no idea what the science behind the 2 news articles actually is. Try reading the papers:

The energy output of the Universe from 0.1 micron to 1000 micron (http://arxiv.org/abs/0803.4164)

The dust effect gives changes luminosity and so in the mass of galaxies of ~20%.
Did you understand Tubbythin's post (his equation applies to ?
So even if we were underestimating the luminosity of a star by a factor of 2, we'd underestimating the mass of the star by a factor of just 1.2. So no, it doesn't make a great deal of difference. (http://forums.randi.org/showpost.php?p=5266885&postcount=152)
(also read about the mass–luminosity relation (http://en.wikipedia.org/wiki/Mass%E2%80%93luminosity_relation) and note that most stars in a galaxy are dwarf stars)
Tubbythin has presented evidence that this will not significantly change the estimate of the mass in stars.


Evidence for a Non-Uniform Initial Mass Function in the Local Universe (http://arxiv.org/abs/0902.0384)

The second paper demonstrates that the IMF function is not universal. It varies from galaxy to galaxy. For certain galaxies, astronomers have been underestimating the proportion of small to big stars.
You have presented no evidence that this will significantly change the estimate of the mass in stars.
Astronomers do not calculate the mass of every galaxy in the universe (we have not observed them all!). They take a sample, calculate an average and appy it to the 100 billion galaxies that are estimated to be in the universe. I suspect that the uncertainty in the 100 billion number is much greater than this effect. The number may even be double this - a whopping 0.8% of the mass & energy in the universe is in stars!


Then there's no "dark matter" either because it's been "seen" in the lensing data. You simply blew your "baryonic mass" estimates in a big way.

There is dark matter. It is called dark matter because it is dark. It does not emit detectable light. It can only be seen gravitationally.
The simple question that I asked you demonstrates that dark matter is made of nonbaryonic matter.


Gah. You're still ignoring the obvious. The things that "separated" were the "baryonic matter" that didn't collide and the "baryonic matter" that did. There no separation of "bayonic" and "non bayronic" matter in that image. That is completely made up in your head. Some of that baryonic matter you can account for, but the vast majority of it you cannot.
Gah. You're still ignoring the obvious and displaying your ignorance yet again:
The intracluster medium (http://en.wikipedia.org/wiki/Intracluster_medium) (or intergalactic medium):
Although the ICM on the whole contains the bulk of a cluster's baryons, it is not very dense, with typical values of 10-3 particles per cubic centimeter. The mean free path (http://en.wikipedia.org/wiki/Mean_free_path) of the particles is roughly 1016 m, or about one lightyear.

You do know that the Bullet cluster is at least 1 megaparsec in width 3,261,6366 lightyears?
That means that normal baryonic particles collide over 3 million times to pass from one side to the other. Normal baryonic particles that collide heat up. Normal baryonic particles that heat up in the ICM produce X-rays that can be detected as in the rest of the Bullet Cluster.

[Reality Check]

The last post I did reminded me that we so not have any confirmation that you are not silly enough to be basing your opinion on just news articles rather than the scientific papers.
So have you answered this post?
Can you please confirm that The energy output of the Universe from 0.1 micron to 1000 micron (http://arxiv.org/abs/0803.4164) and Evidence for a Non-Uniform Initial Mass Function in the Local Universe (http://arxiv.org/abs/0902.0384) are the papers you are referring to?

[Reality Check]

First asked 5 November 2009:
The answer to Can Micheal Mozina answer a simple question? (http://forums.randi.org/showpost.php?p=5274654&postcount=220) post about colliding blobs is not how astronomers confirmed that the Bullet Cluster (http://chandra.harvard.edu/photo/2006/1e0657/), MACS J0025.4-1222 (http://hubblesite.org/newscenter/archive/releases/2008/32/) and Abell 520 (http://en.wikipedia.org/wiki/Abell_520) contain matter that does not interacting electromagnetically like normal matter. The distribution of the dark and visible matter in the clusters was a big clue. The scientific confirmation though is that computer simulations of colliding blobs containing a mixture of normal, gaseous matter and matter that only has gravitational friction show the same properties as in my post:

The dark matter goes straight through the normal matter.
The normal matter collides, slows down and heats up.
As the collision progresses the dark matter emerges from the cluster (the outlying blobs seen in the Bullet Cluster (http://chandra.harvard.edu/photo/2006/1e0657/)).
As more time passes the dark matter reverses direction and heads back into the cluster. MACS J0025.4-1222 (http://hubblesite.org/newscenter/archive/releases/2008/32/) is just entering this stage while Abell 520 (http://en.wikipedia.org/wiki/Abell_520) is well into this stage.
See Dark Matter Part 3.5: When Clusters Collide! (http://scienceblogs.com/startswithabang/2009/09/dark_matter_part_35_when_clust.php)

Michael Mozina: What is wrong with the computer simulations?

P.S. One result of the computer simulations is the prediction that under the right conditions dark matter will from a ring around the cluster.
Here is a news article (since you like these) about a ring of dark matter:
NASA finds further proof of dark matter (http://www.cosmosmagazine.com/news/1324/nasa-finds-further-proof-dark-matter)
(I really dislike that "proof" word - it should be "evidence").

Now we have four observations or dark matter that agree with it not interacting electromagnetically like normal matter!

[Michael Mozina]

I have never noticed any answer. Can you give a link to the post where you state that when 2 blobs of gas made of normal matter collide, most of the matter passes through the blobs without interacting (thus forming 3 blobs)?

http://forums.randi.org/showpost.php?p=5266518&postcount=148

Read it this time.

What is the big deal about *most* of the solar system infrastructure and some of the ISM passing through each other?

[DeiRenDopa]

"Huh?" right back at you. You've essentially falsified your "normal" mass 'guestimates' twice now and yet you refuse to alter your mass guestimates, even in the face of recent evidence to explain *WHY* you keep blowing the mass estimates! It's like a Monty Python skit - "Tis only a scratch....come back and fight you coward....".



BaLOOOOOOOOOOOOOOOny!

It's only evidence that our "normal matter" estimates of point sources (those pesky little stars) are grossly off the mark. It's time to simply scrap your estimates of 'normal' matter and come up with better estimates of "normal matter" because "normal matter" emits light that evidently "normal matter" then absorbs in greater amounts than we first realized.

You're like the individual looking at an unidentified flying objects that immediately makes the wild ass claim that 'it's *definitely* (without any doubt at all) from another planet I tell you!". Balooooooooony.



How exactly did it "annihilate" again to give us all the pretty bright gamma lights in the sky? How come we never see it happen anywhere on Earth, or anywhere inside this solar system? How come it only happens "out there somewhere" where I conveniently can't reach in my human lifetime? How many of these "wild faith" doctrines do I have to swallow hook line and sinker to be a part of the "dark" astronomy cult?



Ya, let's forget all about "qualitatively" verifying anything because you haven't got squat in terms of empirical physics. "Quantitatively" you want me to believe you've accurately counted how many invisible matter faeries fit on the head of pin with "high precision" (with the error bars!) no less. :) Give me a break.



I thought you guys and gals are the "professionals"? Can't you take a break from that dark religion thing of yours to whip something up, or are you so infatuated with the "Dark" thingies that you've dreamed up on paper to try another (empirical) approach?



That would be on hold while I'm earning a living doing something constructive that I can actually sell on the open market. If you "astronomers" had to live on the consumer products that you could sell on the open market based on "dark energy", "inflation", and "dark matter", you'd starve to death, or be sued for false advertising. How about publishing a paper involving something that *is* known to emit gamma rays like "electrical discharges"? Oh ya, I forgot, that's your arch enemy, your version of the devil in your religion. You folks will do anything and everything to avoid the dreaded "EU theory" in all it's evil guises. :)
OK, I'm done.

MM, there is no basis for a discussion with you on this topic (at least, not one based on science).

Take care.

[Perpetual Student]

ok, i'm done.

Mm, there is no basis for a discussion with you on this topic (at least, not one based on science).

Take care.

Επιτέλους!

[Michael Mozina]

OK, I'm done.

MM, there is no basis for a discussion with you on this topic (at least, not one based on science).

Take care.

That is in fact probably true, but it's absolutely not my fault.

It's not my fault that you cannot produce a single gram of something that you claim is many times more abundant than the dirt in my backyard. It's not my fault you can't produce any empirical evidence of this material from a controlled experiment. It's not my fault you can't show me a single instance of "dark matter" ever emitting gamma rays in a controlled experiment.

In terms of the "cause" of those gamma rays, if you were claiming that "electricity did it" you would have absolutely no trouble at all demonstrating that electrical discharges cause the emission of gamma rays here on Earth. You'd have no problem demonstrating that many planets and our own sun emit these wavelengths of energy.

It's really not my personal fault that you decided to claim that "dark matter did it" without so much as a single shred of empirical evidence to support your claim. Evidently all you have is a ton of mathematical lipstick on a metaphysical pig. Since I can't empirically verify any of it, that mathematical lipstick of a presentation is about as useful as numerology. Not one of your claims can be empirically verified in a lab, not the claim of gamma ray emissions, not the claim of longevity of exotic "dark matter", not even the claim that exotic matter exists in the first place! None of it has any effect on anything here on Earth, and 'dark matter" has never emitted one single gamma ray in a controlled test.

Nature has already demonstrated a very effective and simple way of creating gamma rays but it has nothing at all to do with "dark matter". It does have something to do with that dreaded "EU theory" that your industry fears like the plague. That's probably the only reason you won't consider it.

[Reality Check]

http://forums.randi.org/showpost.php?p=5266518&postcount=148

Read it this time.

Read it when you posted oit. Read it again. Nothing about blobs in it. Nothing in it about the actual observations of galactic clusters and the intra-cluster medium.

There seems to be something serious wrong with your ability to understand that these observation are not to do with solar systems and the ISM.


What is the big deal about *most* of the solar system infrastructure and some of the ISM passing through each other?
There is no big deal about *all* of the "solar system infrastructure" passing through each other. That is what stars do when galactic clusters collide. Even the galaxies in the clusters have few collisions.

Stated 6 November 2009 (for the 10th time but maybe you will grasp the concept eventually):
There is a big deal when two blobs of intra-cluster medium (ICM) in colliding galactic clusters collide and

Most of the mass in each of them passes through the other without slowing down or heating up.
Some of the mass in each of them does slow down, heat up and emit X-rays.
Simple physics tells us that all of the mass in the two blobs of intra-cluster medium (ICM) must have collided if it was normal matter.
In Michael Mozina's universe all of the mass must be in the second group.
It is not. Therefore in the real universe most of the mass is not normal matter.


Dark Matter Part 3.5: When Clusters Collide! (http://scienceblogs.com/startswithabang/2009/09/dark_matter_part_35_when_clust.php) has a good description of this. Since you are obviously unable to click the link and read it here is a quote:

Some normal matter is packed together in tight, dense little clumps. Good examples of this are stars and galaxies. When you run two large clusters (spanning millions of light years) into each other, these little clumps hardly ever hit each other, and move with a lot of momentum. What does this mean? They tend to miss one another, and they hardly get slowed down by the friction of moving through the other cluster. In other words, they behave like the little metal balls in a game of "Crossfire". They mostly just pass straight through to the other side.

That leaves us with the gas, which is where most of the normal matter is, and the dark matter. For all intents and purposes, these are distributed over the entire cluster, so they're very diffuse, but also omnipresent. The gas is still made up of protons, neutrons, and electrons, and these tiny particles interact with one another very easily. When they run into each other, they behave similarly to running two jets of water into each other:

There is a lot of friction between them, which (if you remember) both slows them down and also heats them up. The slowing down is why the X-ray-emitting gas is always in the middle of these clusters (in all three cases), and the heating is why the gas becomes energetic enough to emit X-rays! In other words, the gas goes "SPLAT!"

But what of the dark matter? Although it obeys the same gravitational laws of physics, it's missing the main source of friction -- electric charge! In fact, we're pretty sure that dark matter has practically no electromagnetic interactions at all. The friction between dark matter particles (as well as between dark matter and gas) is so small it might as well not even be there at all. Colliding dark matter with itself is as futile as colliding light beams with one another; they might as well not even be there!

[Michael Mozina]

Read it when you posted oit. Read it again. Nothing about blobs in it. Nothing in it about the actual observations of galactic clusters and the intra-cluster medium.

Please read it again RC and look for the term "blob". Better yet, do a "Find" and locate the word "blob". You were talking about blobs way back then and I "dealt" with it then too.

There seems to be something serious wrong with your ability to understand that these observation are not to do with solar systems and the ISM.

It's not my "ability to understand" you, it's my "ability to believe" that statement that I'm having trouble with. What else is there to "collide" other than stars and ISM?

If you tell me it's "dark matter", we're right back to square one. For all you and I know "dark matter" is simply composed of more suns and more ISM than we realize. Unless you have evidence that some other form of matter exists and could be involved, I have no evidence that "Dark matter" is anything other than "ordinary matter" that you simply can't account for.

The weakness of your argument is due to the fact that ordinary matter will often "pass through" rather than collide, but some material, particularly in the ISM will collide. "Normal" matter behaves this way, and therefore there is no evidence that any of this matter is anything other than normal matter. Any other claim is an "extraordinary" claim and requires "extraordinary' support too.

There is no big deal about *all* of the "solar system infrastructure" passing through each other. That is what stars do when galactic clusters collide. Even the galaxies in the clusters have few collisions.

Stated 6 November 2009 (for the 10th time but maybe you will grasp the concept eventually):
There is a big deal when two blobs of intra-cluster medium (ICM) in colliding galactic clusters collide and
[LIST=1]
Most of the mass in each of them passes through the other without slowing down or heating up.

Why? What is the percentage of suns, planets and stars that you expect to actually "collide" during such process?
Some of the mass in each of them does slow down, heat up and emit X-rays.

Those would be the particles that actually interacted, and probably originate in the ISM, not the solar system infrastructure. It may also be related to the where the solar system infrastructure "passed through" the ISM of the other galaxy as "stuff interacted'. There any number of reasons why some material would interact and some would not. Anything "massive" would likely not interact much at all. The cores could/would pass right by one another for all I know.

Simple physics tells us that all of the mass in the two blobs of intra-cluster medium (ICM) must have collided if it was normal matter.
In Michael Mozina's universe all of the mass must be in the second group.
It is not. Therefore in the real universe most of the mass is not normal matter.

Why would all "normal matter" be expected to "collide' rather than just "pass through' in your opinion? Here's where the wheels seem to come off your argument. There no way it's all going to interact with matter in the other galaxy. Much of the solar system infrastructures might pass through intact. The density and composition of the ISM will determine how much material might actually be expected to "collide".

I think I'll devote a separate post to your quote.

[edd]

If you tell me it's "dark matter", we're right back to square one. For all you and I know "dark matter" is simply composed of more suns and more ISM than we realize. Unless you have evidence that some other form of matter exists and could be involved, I have no evidence that "Dark matter" is anything other than "ordinary matter" that you simply can't account for.

Baryon fraction is well constrained in several ways - none of which you would approve of though, I'm sure.

Why? What is the percentage of suns, planets and stars that you expect to actually "collide" during such process?
It's actually quite a straightforward calculation - the collision cross-sections are pretty well known and basically no stars or planets collide in a galaxy merger. Gas does though.


Why would all "normal matter" be expected to "collide' rather than just "pass through' in your opinion? Here's where the wheels seem to come off your argument. There no way it's all going to interact with matter in the other galaxy. Much of the solar system infrastructures might pass through intact. The density and composition of the ISM will determine how much material might actually be expected to "collide".
It's straightforward laboratory-founded kinetic theory of gases. You can calculate the gas density and figure it out simply enough. There's no weird physics at all.

[DazzaD]

For all you and I know "dark matter" is simply composed of more suns and more ISM than we realize. Unless you have evidence that some other form of matter exists and could be involved, I have no evidence that "Dark matter" is anything other than "ordinary matter" that you simply can't account for.

Ok.. I will bite.

Nucleosynthesis
http://www.astro.ucla.edu/~wright/BBNS.html

WMAP
http://wmap.gsfc.nasa.gov/universe/uni_matter.html

[Michael Mozina]

I think I'll take that quote apart, claim by claim and see where we end up....

Some normal matter is packed together in tight, dense little clumps. Good examples of this are stars and galaxies. When you run two large clusters (spanning millions of light years) into each other, these little clumps hardly ever hit each other, and move with a lot of momentum. What does this mean? They tend to miss one another, and they hardly get slowed down by the friction of moving through the other cluster. In other words, they behave like the little metal balls in a game of "Crossfire". They mostly just pass straight through to the other side.

So far, so good. Now of course that this "pass straight through" effect would mean that the "cores" and stars and the planets and asteroids and such would tend to "pass straight through'.

Those cores and basic infrastructure (and any ISM that passed through) are your two primary (blue) "blobs".

That leaves us with the gas, which is where most of the normal matter is,

Well, let's start by noting we made an "assumption" that most of the matter is in the form of a "gas".

and the dark matter.

"Dark matter" or more accurately "unidentified mass". It could be "clumpy" like the first example, or a MACHO type of "dark matter".

For all intents and purposes, these are distributed over the entire cluster, so they're very diffuse, but also omnipresent. The gas is still made up of protons, neutrons, and electrons, and these tiny particles interact with one another very easily.

Now we've made another assumption. We *assumed* that there are charged particles when in fact some of the material could be found in neutral atoms, not necessarily charged particles.

When they run into each other, they behave similarly to running two jets of water into each other:

Er well, sort of, but unless they have the density of water they won't necessarily directly interact with an any particular atom/particle in the other ISM. If they are "bound" in any way, due to say "local cloud density", they may be less likely to interact with other particles in the other ISM.

There is a lot of friction between them, which (if you remember) both slows them down and also heats them up. The slowing down is why the X-ray-emitting gas is always in the middle of these clusters (in all three cases), and the heating is why the gas becomes energetic enough to emit X-rays! In other words, the gas goes "SPLAT!"

Of course the other way to explain "x-rays" involves "electrical current". It just so happens that these are million mile per hour, fast moving charged particles, IOW "current flow' sheets flying past each other at millions of miles per hour relative to one another. That is bound to create "current flow" inside the "plasma sheets" of the ISM of each galaxy.

But what of the dark matter?

What about it? You mean like those neutral atoms in the ISM that this author never mentions?

Although it obeys the same gravitational laws of physics, it's missing the main source of friction -- electric charge!

Ah, then he *IS* talking about those neutral atoms in the ISM he never mentioned.

In fact, we're pretty sure that dark matter has practically no electromagnetic interactions at all.

Er, well neutral atoms interact with the EM field but not like a charged particle. They do tend to "absorb light" and make things seem darker than the really are. :)

The friction between dark matter particles (as well as between dark matter and gas) is so small it might as well not even be there at all. Colliding dark matter with itself is as futile as colliding light beams with one another; they might as well not even be there!

Well, unless two neutral atoms slam into each other, ya, I guess they'd just whiz by each other at millions of miles an hour.

I'm afraid this quote is based upon several assumptions that do not seem to be justified. Most plasma is 'dusty' meaning it's not fully ionized. There will be neutral atoms in the ISM of each galaxy, not simply proton and electrons and other charged ions.

[Michael Mozina]

Baryon fraction is well constrained in several ways - none of which you would approve of though, I'm sure.

Try me. :)

It's actually quite a straightforward calculation - the collision cross-sections are pretty well known and basically no stars or planets collide in a galaxy merger. Gas does though.

Well, surely some gas collides, but it wouldn't all collide.

It's straightforward laboratory-founded kinetic theory of gases. You can calculate the gas density and figure it out simply enough. There's no weird physics at all.

I'm sure that there is nothing weird about the physics of plasma interactions, but the relative speeds and charges of the particles are going to make any "guestimations" pretty difficult at best. How much of the ISM is actually "charged" and how much of it is contained in neutral atoms?

[Michael Mozina]

Ok.. I will bite.

Nucleosynthesis
http://www.astro.ucla.edu/~wright/BBNS.html

Welcome to the conversation. :) Nice link. I liked the graphs and such. Here an example of how they account for "normal matter' in the BB.

The mass fraction in various isotopes vs time is shown at right. Deuterium peaks around 100 seconds after the Big Bang, and is then rapidly swept up into helium nuclei. A very few helium nuclei combine into heavier nuclei giving a small abundance of Li7 coming from the Big Bang. This graph is a corrected version of one from this LBL page. Note that H3 decays into He3 with a 12 year half-life so no H3 survives to the present, and Be7 decays into Li7 with a 53 day half-life and also does not survive.

Never once did they mention any of the half-life expectations of "dark matter", or explain how it is composed and how it was created or destroyed. Pure oversight or did these calculations predate any 'dark matter" discussions? How would dark matter change anything in these calculations?

WMAP
http://wmap.gsfc.nasa.gov/universe/uni_matter.html

Perhaps you could elaborate/explain some of the 'claims' of this link?

You, this computer, the air we breathe, and the distant stars are all made up of protons, neutrons and electrons. Protons and neutrons are bound together into nuclei and atoms are nuclei surrounded by a full complement of electrons. Hydrogen is composed of one proton and one electron. Helium is composed of two protons, two neutrons and two electrons. Carbon is composed of six protons, six neutrons and six electrons. Heavier elements, such as iron, lead and uranium, contain even larger numbers of protons, neutrons and electrons. Astronomers like to call all material made up of protons, neutrons and electrons "baryonic matter".

So far, so good. All the things mentioned show up in 'empirical physics'.

Until about thirty years ago, astronomers thought that the universe was composed almost entirely of this "baryonic matter", ordinary atoms.

So in other words, when I was in college the universe was based on "empirical physics". Right or wrong, there was nothing "mystical" about it.

However, in the past few decades, there has been ever more evidence accumulating that suggests there is something in the universe that we can not see, perhaps some new form of matter.

Perhaps, or perhaps not? What makes them think there is any need for a new form of matter? How do they know they didn't underestimate the amount of ordinary material in a distant galaxy?

http://www.space.com/scienceastronomy/080515-galactic-dust.html
http://www.sciencedaily.com/releases/2009/08/090819145846.htm

[edd]

Try me. :)


DazzaD has already posted BBN constraints. Baryon fraction also affects the CMB power spectrum. I'm sure there's at least one other method I've forgotten (perhaps looking at X-ray emission from clusters?)

[Michael Mozina]

DazzaD has already posted BBN constraints. Baryon fraction also affects the CMB power spectrum. I'm sure there's at least one other method I've forgotten (perhaps looking at X-ray emission from clusters?)

You don't find it even the least bit odd that no one says a word about what's going on with "dark matter' during this process? We have all this technical discussion about baryonic matter, and not a single peep about how "dark matter" was created and/or destroyed in the "creation event"? Isn't that a wee "fishy" to say the least?

[edd]

You don't find it even the least bit odd that no one says a word about what's going on with "dark matter' during this process? We have all this technical discussion about baryonic matter, and not a single peep about how "dark matter" was created and/or destroyed in the "creation event"? Isn't that a wee "fishy" to say the least?

No. We don't know much about dark matter but we do know it doesn't interact much with normal matter, and it doesn't decay fast - or it wouldn't be here for us to measure today.

[Michael Mozina]

No. We don't know much about dark matter

Except you evidently know that it decays and emits gamma rays in quantity x (that is curve fitting exercise to match the Fermi data)? From a skeptics point of view it sure seems like you "know" things about "dark matter" when it's convenient for the purposes of a paper, yet plead ignorance when it's less convenient (like where it comes from, how it's made, etc). :)

but we do know it doesn't interact much with normal matter, and it doesn't decay fast - or it wouldn't be here for us to measure today.

All of these beliefs you have about this theoretical "abnormal (dark) matter" seems to be predicated upon the premise that we originally estimated the "normal matter" correctly in the first place. I have no confidence in that assessment, particularly based on recent revelations.

[DeiRenDopa]

Επιτέλους!
"Finally!" - did iGoogle get it right? What would a rough transliteration of the sound of the word be? (Epitelo??)

[edd]

Except you evidently know that it decays and emits gamma rays in quantity x (that is curve fitting exercise to match the Fermi data)? From a skeptics point of view it sure seems like you "know" things about "dark matter" when it's convenient for the purposes of a paper, yet plead ignorance when it's less convenient (like where it comes from, how it's made, etc). :)


No actually, I don't - as you can perfectly well tell from the posts I made at the start of this thread. You would do well not to misrepresent my views when you've obviously read what I said on the matter before.

I said there are theoretical reasons to think it might and that therefore it is a good idea to go and look for that, in order to test those theories.