Holes in Big Bang

[DeiRenDopa]

That's so weak a response it's actually beneath you sol. Those dark flows are *NOT* supposed to be there sol.Wrong. Although as we discussed some time ago (do you remember?), they probably aren't there. The analysis in those papers is badly flawed.

[...]

It's worth reminding readers what MM is on about.

This (http://fr.arxiv.org/abs/0809.3734) is the first Kashlinski et al. paper on "dark flows", published in ApJ in October 2008 ("A Measurement of Large-Scale Peculiar Velocities of Clusters of Galaxies: Results and Cosmological Implications"; link is to the ArXiV preprint abstract).

According to ADS, this paper has been cited 28 times to date; while not all 28 are concerned with the observations or analyses, some are (I'll leave it to readers to make up their own minds as to the extent that the original Kashlinski et al. conclusion has been independently verified, or not).

Two of the most recent - certainly more recent than the last post on a previous discussion on this, here in the JREF Forum - are "The contribution of the kinematic Sunyaev-Zel'dovich Effect from the Warm Hot Intergalactic Medium to the Five-Year WMAP Data (http://fr.arxiv.org/abs/0905.2582)" and "The velocity-shape alignment of clusters and the kinetic Sunyaev-Zeldovich effect (http://fr.arxiv.org/abs/0904.4765)" (again, links are to the ArXiV preprint abstracts). I think it's accurate to say that a) MM has not read either of these, and b) if he has, he clearly did not understand them.

If any reader is interested in discussing the physics (and astronomy, astrophysics, cosmology) in these two - or any other papers on the topic published since the previous JREF Forum discussion - just say so; I'll be happy to engage in such a discussion.

ETA: I see si has posted links to two other, very recent, papers; FWIW both also cite the original Kashlinski et al paper (and are also worth a read, especially in light of the extraordinary assertions MM has been making).

[sol invictus]

The article also notes that inflation was invented in the early 80's and "dark energy' was added in there in 1998. You don't see a problem there with "prediction"? Suddenly in 1998 the whole known physical universe was relegated to mere "bit player" that makes up less than 5% of the physical universe and 75% of the universe is suddenly made of something nobody had ever heard of before? Come now.

Another non-answer, as the goal posts fly off into the distance... dark energy has no significant effect on the predictions of inflation for the acoustic peaks in the power spectrum. It's no more relevant to this than monopoles. If you knew what any of these things are, you might know that.

Why do you keep shifting your ground, Michael?

Do you or do you not admit you were wrong when you said inflation had made no predictions?

[Michael Mozina]

It's emotionally hard to do, but career-wise, it's actually easy.

Ya, tell that to Arp.

[Michael Mozina]

So that article was a lie, and all the scientists quoted in it were lying. Quite a conspiracy!

Where does the article state this sol?

[Michael Mozina]

Do you or do you not admit you were wrong when you said inflation had made no predictions?

Let's be 100% clear on this point before we go any further. Which specific (be very specific) "prediction" are you claiming was actually "predicted", not postdicted?

[Michael Mozina]

Two of the most recent - certainly more recent than the last post on a previous discussion on this, here in the JREF Forum - are "The contribution of the kinematic Sunyaev-Zel'dovich Effect from the Warm Hot Intergalactic Medium to the Five-Year WMAP Data (http://fr.arxiv.org/abs/0905.2582)"

And they key quote from that papers seems to be right in the abstract:

Our model requires a single extra parameter to describe this new component.

Fudging the numbers - 101: When things don't fit right, add more variables.

[sol invictus]

Let's be 100% clear on this point before we go any further. Which specific (be very specific) "prediction" are you claiming was actually "predicted", not postdicted?

Among other things: the power spectrum of the cosmic microwave background, specifically the fact that the tilt of the primordial spectrum of perturbations was very slightly less than 1, and the pattern of the acoustic peaks, including their locations, and relative magnitudes.

[Michael Mozina]

Among other things:

Which other things (specifically)? Even the article you cited notes that most "predictions" were actually postdictions.

the power spectrum of the cosmic microwave background, specifically the fact that the tilt of the primordial spectrum of perturbations was very slightly less than 1, and the pattern of the acoustic peaks, including their locations, and relative magnitudes.

So this "power spectrum" is unrelated to any influence from 'dark energy'?

[sol invictus]

Which other things (specifically)? Even the article you cited notes that most "predictions" were actually postdictions.

I'm not going to play your "let's shift ground every time I get in trouble" game anymore.


So this "power spectrum" is unrelated to any influence from 'dark energy'?

The power spectrum of primordial perturbations, yes - completely unaffected.

Do you or do you not admit you were wrong when you said inflation had made no predictions?

[DeiRenDopa]

Let's be 100% clear on this point before we go any further. Which specific (be very specific) "prediction" are you claiming was actually "predicted", not postdicted?Among other things: the power spectrum of the cosmic microwave background, specifically the fact that the tilt of the primordial spectrum of perturbations was very slightly less than 1, and the pattern of the acoustic peaks, including their locations, and relative magnitudes.
For those interested in a simplified explanation, of inflation and its predictions, this part of Ned Wright's popular cosmology tutorial (http://www.astro.ucla.edu/~wright/cosmo_04.htm) provides a good intro.

[Ziggurat]

Ya, tell that to Arp.

Arp's problem was not that he went against standard models, his problem was that he was publishing crap, and taking up telescope time with unproductive studies. I know that it's hard for you to distinguish between a conspiracy and recognition of inferior work, but it's real. Physicists LOVE game-changers. But there are damned few of those, and most claims are mistakes or delusions.

[Michael Mozina]

I'm not going to play your "let's shift ground every time I get in trouble" game anymore.

That is exactly why I'm trying to pin you down on specifics and make sure I understand your argument.

The power spectrum of primordial perturbations, yes - completely unaffected.

Do you or do you not admit you were wrong when you said inflation had made no predictions?

I'm not sure at the moment. I need to do some further research now that I know exactly what you're suggesting. I will concede for the time being that I have further research to do. Assuming it pans out as you suggest, I will be happy to admit I was wrong about *ONE* (and only one) actual "prediction' that may or may not have panned out. As even your article notes however *MOST* of what are called 'predictions' were actually 'postdictions" in drag.

[sol invictus]

Assuming it pans out as you suggest, I will be happy to admit I was wrong about *ONE* (and only one) actual "prediction' that may or may not have panned out.

By what bizarre arithmetic do you get "ONE" out of an entire spectrum with many specific features?

[Ziggurat]

By what bizarre arithmetic do you get "ONE" out of an entire spectrum with many specific features?

Go easy on him. Remember, math isn't his strong suit.

[DeiRenDopa]

Ya, tell that to Arp.Arp's problem was not that he went against standard models, his problem was that he was publishing crap, and taking up telescope time with unproductive studies. I know that it's hard for you to distinguish between a conspiracy and recognition of inferior work, but it's real. Physicists LOVE game-changers. But there are damned few of those, and most claims are mistakes or delusions.
I think it's important to note that some of Arp's published work is first class, especially his early papers.

And his early papers on quasars (QSOs, etc) are quite interesting ... at the time, very little was known of these fascinating objects, and ideas on their nature many and varied.

However, it quickly became apparent that Arp's analyses were weak, especially the statistical components (he seemed, and still seems, extraordinarily sensitive to finding patterns 'by eye', but almost blind to testing his findings in an objective, independently verifiable way), and by the mid 1970s there was little scientific merit to much of what he continued to publish.

Regarding his career: AFAIK, he moved to Germany, and has (or had, I suspect he's retired by now) a quite cushy position with the Max Planck Institute (for those who don't know: this is one of the 'to die for' employers, if you are keen on astrophysics), so why so many conspiracy nuts and cranks think he's some kind of martyr is really odd ...

Oh, and the 'telescope time' thing is interesting too: no one denies that the proposals for time on the leading astronomy facilities (both ground- and space-based) exceeds the time available (usually by a factor of several), so there has to be a process for allocating time. It follows that a professional astronomer can reasonably expect to have a significant proportion of his proposals turned down (Jim Gunn and John Bahcall may be exceptions); why should Arp be different? One thing I find fascinating is when you ask ardent Arp fans, or even proponents of crank science (such as "EU theory"), what they'd do if they had unlimited access to the world's best facilities, you get either silence or gibberish ("I'd give it to Arp" is perhaps the worst cop-out)!

[sol invictus]

I'm not sure at the moment. I need to do some further research now that I know exactly what you're suggesting.

Translation: you won't hear from me again on that. But in a few months (or less) I'll go back to saying exactly the same things that started this little debate.

[Michael Mozina]

Among other things: the power spectrum of the cosmic microwave background, specifically the fact that the tilt of the primordial spectrum of perturbations was very slightly less than 1, and the pattern of the acoustic peaks, including their locations, and relative magnitudes.

What's the oldest paper you can cite the includes these "predictions"?

[Michael Mozina]

Translation: you won't hear from me again on that. But in a few months (or less) I'll go back to saying exactly the same things that started this little debate.

And that's what I get for trying to be in integrity eh?

[sol invictus]

What's the oldest paper you can cite the includes these "predictions"?

These early papers 1982 had most of it right:

http://www.adsabs.harvard.edu/abs/1982PhRvL..49.1110G
http://www.adsabs.harvard.edu/abs/1982PhLB..115..295H

The details were worked out over the following decade. By 1996 just about the whole picture was there:

http://arxiv.org/abs/astro-ph/9510117

WMAP released its first data in 2003.

[sol invictus]

And that's what I get for trying to be in integrity eh?

Sorry Michael, but you've done it several times now. You did it with dark flows, with expanding space, with dark energy, with that paper on EM fields as dark energy, with your iron sun model. After a while, a pattern emerges. For how long do you expect me to give you the benefit of a doubt?

[Michael Mozina]

Sorry Michael, but you've done it several times now. You did it with dark flows,

Are you trying to claim that I am *OBLIGATED* to agree with you when you throw a paragraph at me from somewhere? Just because you *CAN* add variables to your theory doesn't mean you *SHOULD* do so, or that I am obligated to accept your "explanation" that you *CAN* manipulate things to make it fit. I never doubted that part in the first place.

with expanding space,

What about it? Again, you seem to insist I *MUST* agree with your personal 'interpretation" because you say so.

with dark energy, with that paper on EM fields as dark energy,

Gee, that may actually be a valid complaint.

with your iron sun model.

Sure. Like every solar model was instantly put forth, and every OTHER solar model has resolved and explained every solar phenomenon, right? Hell, you folks won't even *TOUCH* those images on my website, deal with solar wind, or anything that actually put holes in your theory. It's fine for you to ignore the weaknesses of your own solar model, but I'm *PERSONALLY* obligated to answer every question under the sun on your personal timeline.

After a while, a pattern emerges. For how long do you expect me to give you the benefit of a doubt?

The "pattern" that emerges on your side is your total unwillingness to deal with *ANY* of the images on my website, and your side's insistence at arguing every point from a place of pure ignorance. White light images? What white light images? Flying stuff? What flying stuff. Please.

[Michael Mozina]

These early papers 1982 had most of it right:

Thanks for the links. So what did they get wrong? How many points do I have to award them if *SOME* things were correct and *SOME* were "off' by a bit?

[DeiRenDopa]

What have i done now?
You posted some comments; fine.

Others responded, with explanations, questions, requests for clarifications, etc, etc, etc.

You posted some more comments, answered some questions, provided some clarifications, etc, etc, etc.

And so on, over several pages.

THEN you reverted to making the same bald assertions as you had made back on page one (and even in the OP) ... as if the many, many posts in between did not exist.

Such behaviour is characteristic of a troll.

However, you also noted that you are under the weather today, so perhaps it's just that your memory isn't good today, and that you forgot to check the posts earlier in the thread before repeating yourself?

Questions?

[Singularitarian]

Yes, well, i can't wait for those days ...


..stares somewhere

[sol invictus]

Thanks for the links. So what did they get wrong? How many points do I have to award them if *SOME* things were correct and *SOME* were "off' by a bit?

Dunno - you decide. There's a very large literature, but the essential physics is in those 1982 papers, and just about every detail relevant here is in that 1995/6 paper (published 8 years before WMAP's first data release).

[Michael Mozina]

By the way sol, would you mind citing the specific line from the dark energy/EM field paper you didn't agree with again? I recall you (actually I didn't remember it was you to be honest) did in fact cite a specific line number, but I don't recall which one.

[sol invictus]

By the way sol, would you mind citing the specific line from the dark energy/EM field paper you didn't agree with again? I recall you (actually I didn't remember it was you to be honest) did in fact cite a specific line number, but I don't recall which one.

Eq. 15 (although many of the rest are wrong too).

[Michael Mozina]

Eq. 15 (although many of the rest are wrong too).
Thank you.

[Michael Mozina]

So, if I may ask, why do you post here, in the Science, Mathematics, Medicine, and Technology section of the JREF Forum?

For avoidance of doubt, I'm not asking about why you write posts which contain questions (about Science, Mathematics, Medicine, and Technology); I'm asking why you post bald assertions (about Science, Mathematics, Medicine, and Technology) with no apparent intention of engaging in discussion of them.

Translation: If you dare to question them, be prepared to be grilled mercilessly till you can't answer a specific question, and then expect to be skewered publicly for your crime.

[Singularitarian]

So, if I may ask, why do you post here, in the Science, Mathematics, Medicine, and Technology section of the JREF Forum?

For avoidance of doubt, I'm not asking about why you write posts which contain questions (about Science, Mathematics, Medicine, and Technology); I'm asking why you post bald assertions (about Science, Mathematics, Medicine, and Technology) with no apparent intention of engaging in discussion of them.

I will give you the same answer i gave someone a couple of weeks back.

I am simply here to inspire this place for all that it was intended. You want skepticism, you can have skepticism. I am simply trying to entice some intelligent conversations.

[DeiRenDopa]

I will give you the same answer i gave someone a couple of weeks back.

I am simply here to inspire this place for all that it was intended. You want skepticism, you can have skepticism. I am simply trying to entice some intelligent conversations.
Thanks.

A conversation requires the active participation of more than one party ... if, as you say, you don't care what anyone thinks, does that mean you do not intend to engage in any conversations (intelligent or otherwise)?

I'm also curious about "skepticism" ... as I said earlier, asking questions seems fine, but making bald assertions and then not engaging with anyone on any responses (or, worse, simply repeating the assertions as if nothing had happened in between) can't really be called scepticism, can it? I mean, it's almost the essence of trolling, isn't it?

[Paul]

I am simply here to inspire this place for all that it was intended. You want skepticism, you can have skepticism. I am simply trying to entice some intelligent conversations.You have a very strange way to inspire people.

You came here proclaiming your superior knowledge while demonstrating a distinct lack thereof. You dismissed others' knowledge and education as inferior, only to confirm that you have yet to study physics at a university level, ignoring the advice and help offered by people who's knowledge goes beyond your own aspirations ("certaified Doctor in astrophysical and exobiological sciences" isn't it?).

In what way do expect such behaviour will inspire people to converse with you?

[Singularitarian]

You have a very strange way to inspire people.

You came here proclaiming your superior knowledge while demonstrating a distinct lack thereof. You dismissed others' knowledge and education as inferior, only to confirm that you have yet to study physics at a university level, ignoring the advice and help offered by people who's knowledge goes beyond your own aspirations ("certaified Doctor in astrophysical and exobiological sciences" isn't it?).

In what way do expect such behaviour will inspire people to converse with you?
Excuse me.

Truth be told, i had people flouting their education to me. It was their general attitudes to me originally in which i retaliated. This feeble attempt you make is nothing but dillusional lies.

When people said i was wrong on things i knew i was right about i.e. the square of the wave function (an amplitude process) defines a collapse in the system \int_{\Omega} |\psi|^2 and i don't know how many times i had to state this. In fact, there are many instances in which i've had to entertain this behaviour.

Also, i never bring anyone down for their education. If i have ever brought anyone down, they have started on me.

[Michael Mozina]

These early papers 1982 had most of it right:

http://www.adsabs.harvard.edu/abs/1982PhRvL..49.1110G
http://www.adsabs.harvard.edu/abs/1982PhLB..115..295H

The details were worked out over the following decade. By 1996 just about the whole picture was there:

http://arxiv.org/abs/astro-ph/9510117

WMAP released its first data in 2003.

I still fail to understand how you figure these are true "predictions". Let's look at abstracts first:

Abstract
The consequences of the quantum fluctuations of the scalar Higgs field, phi, that occur during the era of exponential expansion are examined. The evolution of these fluctuations is followed through the time at which galactic scales come within Hubble radius (at approximately 10 to the 8th sec), and the energy density fluctuations delta-rho/rho at that time are estimated. It is noted that according to Harrison (1970) and Zeldovich (1972), this number should be about 0.0001 and should be roughly independent of scale. It is found that the new inflationary universe leads to a delta-rho/rho which is roughly independent of scale, but with a magnitude of approximately 50. It is therefore thought that a further modification of this scenario is necessary in order to make it workable.

Emphasis mine.

The horizon, flatness and monopole problems can be solved if the universe underwent an exponentially expanding stage which ended with a Higgs scalar field running slowly down an effective potential. In the downhill phase irregularities would develop in the scalar field. These would lead to fluctuations in the rate of expansions which would the have right spectrum to account for the existence of galaxies. However the amplitude would be too high to be consistent with observations of the isotropy of the microwave background unless the effective coupling constant of the Higgs scalar was very small.

Emphasis mine.

In both cases the authors seem to be "working backwards" to match a specific set of observations and/or specific concerns that have already been voiced. How exactly do you figure this is a real "prediction" if they start off trying to match something they have already observed?

[sol invictus]

Insane, reading what posts remain while mine get edited out.


Agreed. Two of my posts - which contained rather carefully written answers to some issues we were discussing regarding the size of the electron - were moved. I'm creating a thread on the management forum to complain.

Complaint thread: http://forums.randi.org/showthread.php?t=151435

moved posts: http://forums.randi.org/showthread.php?t=151427

[sol invictus]

Repost #1:

In case anyone is curious, in reality-based physics electrons are believed to be point particles. What that means is that they don't appear to have any substructure or length scale one can associate with a size (unlike a proton, for example, which has a substructure of definite size which becomes visible when you probe it with something sufficiently small).

But that does not mean that electrons occupy and affect only a single point. The reason is that quantum mechanics smears them over a region of non-zero size. They should be thought of as probability clouds. Anything which passes through that cloud has some probability of interacting with the electron.

But the size of the cloud depends on the state of the electron, on its momentum, on its surroundings - not on some intrinsic property all electrons share. So there is nothing analagous to a radius. And the harder you smack an electron, the smaller it looks - because the size of the cloud decreases with increasing interaction energy.

----------
Repost #2:

So, as for the radius of the electron - see my post just above. Electrons don't have a radius. There's a quantity sometimes called the classical radius of the electron, but that ignores quantum mechanics and doesn't mean much. Something that's more useful is the Compton wavelength - that's more or less the radius of the electron's probability cloud when it's at rest and in vacuum. But that cloud isn't "hard", and its size depends on quantum mechanics and the electron's energy only.

[Piggy]

Translation: If you dare to question them, be prepared to be grilled mercilessly till you can't answer a specific question, and then expect to be skewered publicly for your crime.

Translation: If you make assertions to experts in any field which don't match what is known in that field, be prepared to be questioned about those assertions, and if you can't produce justifiable answers, then expect to have this fact pointed out to you.

[Perpetual Student]

Repost #1:

In case anyone is curious, in reality-based physics electrons are believed to be point particles. What that means is that they don't appear to have any substructure or length scale one can associate with a size (unlike a proton, for example, which has a substructure of definite size which becomes visible when you probe it with something sufficiently small).

But that does not mean that electrons occupy and affect only a single point. The reason is that quantum mechanics smears them over a region of non-zero size. They should be thought of as probability clouds. Anything which passes through that cloud has some probability of interacting with the electron.

But the size of the cloud depends on the state of the electron, on its momentum, on its surroundings - not on some intrinsic property all electrons share. So there is nothing analagous to a radius. And the harder you smack an electron, the smaller it looks - because the size of the cloud decreases with increasing interaction energy.

----------
Repost #2:

So, as for the radius of the electron - see my post just above. Electrons don't have a radius. There's a quantity sometimes called the classical radius of the electron, but that ignores quantum mechanics and doesn't mean much. Something that's more useful is the Compton wavelength - that's more or less the radius of the electron's probability cloud when it's at rest and in vacuum. But that cloud isn't "hard", and its size depends on quantum mechanics and the electron's energy only.

If we had a cloud of electrons and bombarded it with a beam of very high energy electrons, could any of the electrons in the beam strike and bounce back from any of electrons in the cloud?

[Dancing David]

I know its too big. I have consulted with a physicist who was working on it. He assured me big bang did not predict a void of that magnitude.

That is not a citation, nor a source.

[Paul]

Without derailing too much I hope -

Truth be told, i had people flouting their education to me. It was their general attitudes to me originally in which i retaliated.You only joined in july, and by the 15th you'd already been warned about bad language and personal attacks.

The following quotes of yours are from only two threads: GO LEARN SOME PHYSICS AND STOP DECIEVING PEOPLE WHO ARE TRYING TO TAKE AN INTEREST IN THE WORK.

I implore you not to listen to him.He does not know what he is talking about.

Neveretheless, if some of you actually learned some physics instead of raising voices for a reason which is just as insipid as you would expect from a primary school patter, then until such a conversation evolves, then maybe i will be more complient, and hopefully so will you and others.

Go learn some of the physics first before you want to debate them please.

And there is no-way in hell you are a scientist. I am a Graduate in physics, and i can tell you lack drammatically in physics knowledge.

Sorry guys, but the general attitude here is as degradated as the knowledge of physics being flung about.

You lot must be sitting in a room together eating a magic-mushroom stew, because, i can assure you, my contrbutions have been 100% scientifically-accurate within these discussions in this thread, i have had enough for now.



This feeble attempt you make is nothing but dillusional lies. What were you saying?


Also, i never bring anyone down for their education. If i have ever brought anyone down, they have started on me.We know that's a lie, and this whole victim thing is going to cause problems when you go to university.

[Singularitarian]

That is not a citation, nor a source.



The obvious must have escaped me :rolleyes:

[Reality Check]

I still fail to understand how you figure these are true "predictions". Let's look at abstracts first:

In both cases the authors seem to be "working backwards" to match a specific set of observations and/or specific concerns that have already been voiced. How exactly do you figure this is a real "prediction" if they start off trying to match something they have already observed?
The basic fact is that scientific papers often mention earlier results and the need to reconcile any differences between these results and their results.
For example a guy called Einstein did a lot of "working backwards" to match a specific set of observations.

IMHO first 2 papers are not about the predictions. As sol stated "These early papers 1982 had most of it right:", i.e. the it he is talkig about is inflation.

The third paper was published at a pont where the predictions are fully worked out and not yet observed
Small Scale Cosmological Perturbations: An Analytic Approach (http://arxiv.org/abs/astro-ph/9510117)
Through analytic techniques verified by numerical calculations, we establish general relations between the matter and cosmic microwave background (CMB) power spectra and their dependence on cosmological parameters on small scales. Fluctuations in the CMB, baryons, cold dark matter (CDM), and neutrinos receive a boost at horizon crossing. Baryon drag on the photons causes alternating acoustic peak heights in the CMB and is uncovered in its bare form under the photon diffusion scale. Decoupling of the photons at last scattering and of the baryons at the end of the Compton drag epoch, freezes the diffusion-damped acoustic oscillations into the CMB and matter power spectra at different scales. We determine the dependence of the respective acoustic amplitudes and damping lengths on fundamental cosmological parameters. The baryonic oscillations, enhanced by the velocity overshoot effect, compete with CDM fluctuations in the present matter power spectrum. We present new exact analytic solutions for the cold dark matter fluctuations in the presence of a growth- inhibiting radiation {\it and} baryon background. Combined with the acoustic contributions and baryonic infall into CDM potential wells, this provides a highly accurate analytic form of the small-scale transfer function in the general case

[Michael Mozina]

The basic fact is that scientific papers often mention earlier results and the need to reconcile any differences between these results and their results.

Sure, but let's be clear about the difference between a real "prediction" of something unexpected you might learn from a controlled experiment and a "postdiction" that is based upon the idea of attempting to match a *KNOWN* and *MEASURED* quantity.

Birkeland's empirical experiments led to true "predictions" because he actually 'learned' something from his experiments that his did not expect to discover, whereas these papers seem to be attempting to 'fit' something that has already been measured and doesn't seem to jive with previous incarnations of "inflation".

[tsig]

Translation: If you dare to question them, be prepared to be grilled mercilessly till you can't answer a specific question, and then expect to be skewered publicly for your crime.

That's the way it works. Not just here at Jref but in real life also.

[tsig]

Sure, but let's be clear about the difference between a real "prediction" of something unexpected you might learn from a controlled experiment and a "postdiction" that is based upon the idea of attempting to match a *KNOWN* and *MEASURED* quantity.

Birkeland's empirical experiments led to true "predictions" because he actually 'learned' something from his experiments that his did not expect to discover, whereas these papers seem to be attempting to 'fit' something that has already been measured and doesn't seem to jive with previous incarnations of "inflation".

What "is" this: An argument from parentheses?

[Michael Mozina]

What "is" this: An argument from parentheses?

:)

[ben m]

When people said i was wrong on things i knew i was right about i.e. the square of the wave function (an amplitude process) defines a collapse in the system \int_{\Omega} |\psi|^2 and i don't know how many times i had to state this. In fact, there are many instances in which i've had to entertain this behaviour.


... about which you are still either (a) wrong, (b) typo-ridden, or (c) stating things so unclearly that it can't be interpreted as correct.

The quantity \int_{\Omega} \mid \psi \mid^2, presuming you mean an integral over space at any fixed time, is equal to 1 by definition or normalization. This is true whether or not you make an observation of any quantity; I know of no one who would call this "collapse", but you called it "the definition of collapse". The various other integrals you seemed to be suggesting---including some time term or something---were unintelligible.

There is a sense in which a quantity like \mid \psi(\vec{r})\mid^2, perhaps integrated over a finite region of space, has something to do with collapse---that quantity (limited space integral, no time integral) is the probability of finding a particle at position r. That is a quantity sort of related to collapse---pedagogically speaking, you might say " you have to collapse an unknown wavefunction onto position eigenvalues in order to find these probabilities", but even this isn't really true. (Example: to I prepare a ground-state H atom, I measure E, not position---but having measured E, and solved the Schrodinger equation, I know phi(r) everywhere, and thus |phi(r)|^2, but that doesn't mean I "know where the electron is" or that I have "measured r".

But that's not what you had said at all. You had said something very specifically wrong using vaguely quantum-looking notation. IIRC you'd had unit trouble as well (as usual?) and called a quantity with time units a probability, or something.

[Singularitarian]

... about which you are still either (a) wrong, (b) typo-ridden, or (c) stating things so unclearly that it can't be interpreted as correct.

The quantity http://www.randi.org/latexrender/latex.php?%5Cint_%7B%5COmega%7D%20%5Cmid%20%5Cpsi% 20%5Cmid%5E2, presuming you mean an integral over space at any fixed time, is equal to 1 by definition or normalization. This is true whether or not you make an observation of any quantity; I know of no one who would call this "collapse", but you called it "the definition of collapse". The various other integrals you seemed to be suggesting---including some time term or something---were unintelligible.

There is a sense in which a quantity like http://www.randi.org/latexrender/latex.php?%20%5Cmid%20%5Cpsi%28%5Cvec%7Br%7D%29%5C mid%5E2, perhaps integrated over a finite region of space, has something to do with collapse---that quantity (limited space integral, no time integral) is the probability of finding a particle at position r. That is a quantity sort of related to collapse---pedagogically speaking, you might say " you have to collapse an unknown wavefunction onto position eigenvalues in order to find these probabilities", but even this isn't really true. (Example: to I prepare a ground-state H atom, I measure E, not position---but having measured E, and solved the Schrodinger equation, I know phi(r) everywhere, and thus |phi(r)|^2, but that doesn't mean I "know where the electron is" or that I have "measured r".

But that's not what you had said at all. You had said something very specifically wrong using vaguely quantum-looking notation. IIRC you'd had unit trouble as well (as usual?) and called a quantity with time units a probability, or something.

When i said the collapse is defined by the square of the absolute wave function i am;

100% correct.
Completely right in saying so, since statistically it is how it is defined.
Written in the way given, is not decieving at all. You can try and wriggle out this again, but... sigh, i implore you realize that this is an amplitude process finding the most ''likely'' event, hence, you will find this likely event upon such a collapse.

I do remember you where somewhat clueless as well. You didn't seem to recognize amplitude equations. At least you can now.

As per rule 12, attack the argument, not the arguer.

[Molinaro]

When i said the collapse is defined by the square of the absolute wave function i am;

100% correct.
Completely right in saying so, since statistically it is how it is defined.
Written in the way given, is not decieving at all. You can try and wriggle out this again, but... sigh, i implore you realize that this is an amplitude process finding the most ''likely'' event, hence, you will find this likely event upon such a collapse.

I do remember you where somewhat clueless as well. You didn't seem to recognize amplitude equations. At least you can now.

It is getting realy sad to watch you fail so badly so continuously. You can't even understand what's been said to you. Hence you blissfully delude yourself into believe you are still right.

You can't even recognize what's right when it's spelled out for you! And then you will no doubt continue to post after this about how you proved us wrong!

[Singularitarian]

It is getting realy sad to watch you fail so badly so continuously. You can't even understand what's been said to you. Hence you blissfully delude yourself into believe you are still right.

You can't even recognize what's right when it's spelled out for you! And then you will no doubt continue to post after this about how you proved us wrong!

Ben is intentionally bringing things in that are not needed in a mathematical shorthand, such as operators describing observation.

And to prove you can do what i did, i will find yet more evidence.

[Singularitarian]

So i have been talking about the absolute sqaure of the wave function:

http://en.wikipedia.org/wiki/Wave_function

Indeed, if it has anything to do with the collapse itself, then one would find obvious relations. Oh, look, the wiki page page has a related article on it... Damnations batman!

All the shorthand says is finding the probability of a particle in location x or /and a time. You cannot have that probability unless there is a deflation in the wave function. I know these things. I have studied them for a long time.

[Molinaro]

The point that you seem eager to ignore is that the equation as you wrote it is wrong. Trying to call it mathematical shorthand is just a cop out. That running theme in your posts is getting old. If you can't write an equation correctly you cannot at the same time claim that you are right.

We only have what you post here to go by, and when that's shown to be wrong could you not just once accept that you were wrong?

[Singularitarian]

The point that you seem eager to ignore is that the equation as you wrote it is wrong. Trying to call it mathematical shorthand is just a cop out. That running theme in your posts is getting old. If you can't write an equation correctly you cannot at the same time claim that you are right.

We only have what you post here to go by, and when that's shown to be wrong could you not just once accept that you were wrong?

Its not cop out at all, not within the context it was used in at the time.

I was going to post this:
,............................................

Edited for Rule 12 you can argue that it requires to be observer-dependant:

http://www.springerlink.com/content/m26577k447513844/

''Abstract Probability distributions are seen to be observer dependent. The probability function http://www.randi.org/latexrender/latex.php?%5Cpsi%20%5Cdagger%20%5Cpsi can be put into an observer-dependent form. This eliminates the acausal behavior of the collapse of the wave function.''

[Raze]

So i have been talking about the absolute sqaure of the wave function:

http://en.wikipedia.org/wiki/Wave_function

Indeed, if it has anything to do with the collapse itself, then one would find obvious relations. Oh, look, the wiki page page has a related article on it... Damnations batman!

All the shorthand says is finding the probability of a particle in location x or /and a time. You cannot have that probability unless there is a deflation in the wave function. I know these things. I have studied them for a long time.

So does anyone who has had three semesters of university physics. What's your point?



The hard part is to actually work with the mathematics of a wave function, rather than to just state the very very basics. I mean, reciting that the square of the absolute value of a wave function is the probability density, and that the integral over some distance of the probability density gives the probability of a measurement of the particle's position giving a value within the interval require nothing but the reading of a wikipedia article.

Explaining the math requires a bit more. Actually solving partial differential equations or actually doing calculations with these things is what would impress me. Not reciting definitions that can be found on any generic internet article.


So again, what's your point?

[Singularitarian]

Read back, i'm not going over it again.

[Raze]

Read back, i'm not going over it again.

Maybe I'm confusing threads, but in this one were you saying that the people debating you didn't know anything about the wave function, etc?

[ben m]

When i said the collapse is defined by the square of the absolute wave function i am 100% correct.


We have a term for the square of the absolute wavefunction (not integrated) This term is the "probability density". It is not "the definition of collapse".

We have a term for the all-space integral of the absolute square; this word is "set to 1 by normalization".

We do not have a term for the time-integral (which you specified---remember?) of the all-space integral, because nobody does that.

Collapse onto a position eigenstate does, indeed, involve a drawing from the probability density that you stated (or rather, that you claim you were trying to state). Collapse onto a momentum eigenstate, or an energy eigenstate, or a squeezing eigenstate, or whatever, does not draw from |phi|^2---it's not somehow fundamental to collapse, it's one of many equally-interesting probability distributions sampled by QM.

Let me give an example. If I measure the energy level of an atom, I collapse its wavefunction onto an energy eigenstate. Have I drawn a probability from your |psi|^2? Do I know where the particle is?

[edd]

Excuse me.

Truth be told, i had people flouting their education to me. It was their general attitudes to me originally in which i retaliated. This feeble attempt you make is nothing but dillusional lies.

Truth be told?
http://forums.randi.org/showpost.php?p=4905836&postcount=10 - you are first to raise the matter of your qualifications. The previous poster said that they themselves had no qualifications - not something one would consider 'flaunting'.
http://forums.randi.org/showpost.php?p=4906231&postcount=50 - I suggest that it's not wise for you to flaunt your education to us
http://forums.randi.org/showpost.php?p=4906336&postcount=55 - I clarify that I mean specifically that it's better all round if noone waves qualifications about as it's better to just look at the arguments
http://forums.randi.org/showpost.php?p=4919883&postcount=182 - you finally invite us to flaunt our education:

It appears quite a few people here don't actually know the quantum laws of physics very well - what age are you, and what levels of degrees do you have in the mechanics of physics, i.e any crudentials you could boast and put me to shame about?

By the way, while skeptic and sceptic are the same word spelt differently, flout and flaunt are not.

[Singularitarian]

Truth be told?
http://forums.randi.org/showpost.php?p=4905836&postcount=10 - you are first to raise the matter of your qualifications. The previous poster said that they themselves had no qualifications - not something one would consider 'flaunting'.
http://forums.randi.org/showpost.php?p=4906231&postcount=50 - I suggest that it's not wise for you to flaunt your education to us
http://forums.randi.org/showpost.php?p=4906336&postcount=55 - I clarify that I mean specifically that it's better all round if noone waves qualifications about as it's better to just look at the arguments
http://forums.randi.org/showpost.php?p=4919883&postcount=182 - you finally invite us to flaunt our education:


By the way, while skeptic and sceptic are the same word spelt differently, flout and flaunt are not.

I never came here saying ''and here is my qualifications.''

Other people assisted me in that area.

[Singularitarian]

And the posts you have given mischaracterizes how those qoutes came into play.

By the way, i did once say i had a Diploma, but i can assure you, someone else already had the pleasure of tellling everyone this anyway.

[edd]

I thought this would be interesting to recite. I was just reading this article by Doctor Cramer

http://www.npl.washington.edu/AV/altvw141.html

Incidentally I think the indicated position for the cold spot is about 180 degrees out in galactic latitude. The cold spot is on the bottom right - it's that blue/black region.

[Singularitarian]

We have a term for the square of the absolute wavefunction (not integrated) This term is the "probability density". It is not "the definition of collapse".

We have a term for the all-space integral of the absolute square; this word is "set to 1 by normalization".

We do not have a term for the time-integral (which you specified---remember?) of the all-space integral, because nobody does that.

Collapse onto a position eigenstate does, indeed, involve a drawing from the probability density that you stated (or rather, that you claim you were trying to state). Collapse onto a momentum eigenstate, or an energy eigenstate, or a squeezing eigenstate, or whatever, does not draw from |phi|^2---it's not somehow fundamental to collapse, it's one of many equally-interesting probability distributions sampled by QM.
Indeed, the

to find any state, even a collapse in the wave function, the equations use probability statistical analysis. The normalization is defined as the real ''thing'' which remains, not a smear of probability.

This has been dragging long enough. Back to topic.

[edd]

And the posts you have given mischaracterizes how those qoutes came into play.
I'll happily be corrected on that, I didn't reread threads entirely, just those parts I recalled of them.

[Singularitarian]

I'll happily be corrected on that, I didn't reread threads entirely, just those parts I recalled of them.

You might be interested to know, that when i first came here and posted a few essays, someone had given up my identity as being the same user on another forum called ''student forum'', which by the way had all the information about me, such as my education.

[edd]

You might be interested to know, that when i first came here and posted a few essays, someone had given up my identity as being the same user on another forum called ''student forum'', which by the way had all the information about me, such as my education.

Very well. As I said I don't think the discussions of qualifications are useful, although it seemed from what I'd read before that the above was rather backwards. If there were posts referencing things elsewhere I'd have missed them and can understand that it might have led where it has, in which case apologies.

[Singularitarian]

I agree, hence my earlier anger when i first came here, when people where saying i was ''arguing'' with physicists. This is how the debates above really came into play, and i was challenging exactly where these physicists where.

I too, do not like people who flaunt their knowledges.

[Gaspode]

Back on topic please. Discuss the subject of the thread, not each other.

[Michael Mozina]

Back on topic please. Discuss the subject of the thread, not each other.

Will do.

[ben m]

Indeed, the

to find any state, even a collapse in the wave function, the equations use probability statistical analysis.


There are probabilities involved, but the specific probability you claim you to have been writing, |phi|^2, is specifically a position probability density. It us not "used to find any state", it's not used in all cases of "collapse", it's something narrowly specific to position measurements. I gave an example of a quantum measurement and collapse which has nothing to do with |phi|^2.


The normalization is defined as the real ''thing'' which remains, not a smear of probability.


I cannot parse this statement. The probability density is indeed normalized; the probability of the particle being *somewhere* is exactly 1. Therefore, the *sum* of the probability of being at each individual position is also 1. "probability of being at x" = |phi(x)|^2. "sum of probability at x for all values of x" = integral |phi(x)|^2 dx = 1. That's normalization.


This has been dragging long enough. Back to topic.

You brought it up. You're welcome to bump the old threads---the "relativity quiz" would be a good place to start IMO.

[Michael Mozina]

Sol...

Unless you have some other references I'm going to stick to my statement that to my knowledge all inflation 'predictions' are actually "postdicted' from earlier observations. That certainly seems to be the case with both of the early papers you cited.

As it relates to the DE/EM issue, I'm still doing some background reading and I have not reached a final conclusions just yet. You may be interested in noting that this is one of 11 different papers on this topic written by these authors. It's unclear to me at the moment how many (if any) of these papers has actually been peer reviewed.

http://arxiv.org/find/astro-ph/1/au:+Jimenez_J/0/1/0/all/0/1

[sol invictus]

Sol...

Unless you have some other references I'm going to stick to my statement that to my knowledge all inflation 'predictions' are actually "postdicted' from earlier observations. That certainly seems to be the case with both of the early papers you cited.

What? Why?

It's true that it was known in the early 1980s that a roughly flat primordial spectrum over some range of scales would probably be consistent with observations, but that's it (and that's why those guys were excited about their results). But inflation predicted something much more specific, only the first rough version of which is in those 1982 papers. By 1996 paper there were many details (like the acoustic peaks), none of which were observed until years later.

As it relates to the DE/EM issue, I'm still doing some background reading and I have not reached a final conclusions just yet.

OK.

[Michael Mozina]

What? Why?

Did you see my earlier post on the two earliest papers you cited? You haven't responded to it yet, unless of course I missed it.

It's true that it was known in the early 1980s that a roughly flat primordial spectrum over some range of scales would probably be consistent with observations, but that's it (and that's why those guys were excited about their results).

But the authors are actively "curve fitting' inflation theory to known observations in those earlier papers.

By 1996 paper there were many details (like the acoustic peaks), none of which were observed until years later.

I guess I'll have to go through the later paper then with a bit more focus on what (if anything) is actually a 'prediction' vs. what is simply a curve fit to a known observation. It is however quite clear that some of these features were already "observed" by the time the first papers were written and in those earlier papers, inflation theory is being revised to take these previous observations into account. That is postdiction, not prediction.

I suppose it's 'possible' to "predict" some some features based purely on mathematical models, but typically, most "predictions' are based upon something that is learned from active experimentation, not simply a mathematical model. GR theory shows that there are exceptions to that rule however.

[Perpetual Student]

What? Why?

It's true that it was known in the early 1980s that a roughly flat primordial spectrum over some range of scales would probably be consistent with observations, but that's it (and that's why those guys were excited about their results). But inflation predicted something much more specific, only the first rough version of which is in those 1982 papers. By 1996 paper there were many details (like the acoustic peaks), none of which were observed until years later.




This appears to be a gray area. Initially, inflation was needed to account for observed characteristics of the universe like homogeneity, etc. Later, it was realized that a totally homogeneous era could not lead to the structure currently observed --- some inhomogeneity was needed. As I recall, quantum fluctuations were then presented as the likely cause of the primordial lumpiness leading to galaxy formation, etc. Then, a search for inhomogeneities in the CMB ensued -- and were found.
Would there not have to be quantum fluctuations anyway, for galaxies to form, with or without inflation? Are there not other possible explanations for the CMB and its irregularities? It seems that MM's view that aspects of inflation theory are "postdicted" might have some merit.

[sol invictus]

Did you see my earlier post on the two earliest papers you cited? You haven't responded to it yet, unless of course I missed it.

Oops, missed it. What they're saying is that they know that a flat spectrum with amplitude around 10^-5 would roughly fit data. But it's very rough, because at the time no precise data was available - and didn't become available until 20 years later.

Typical inflation models, as I've told you, have 1 or 2 parameters, 1 or 2 numbers that must be put in. As with any scientific theory, you use 1 or 2 numbers from data to fix those (in this case, 10^-5 as the overall amplitude). Everything else you get out is a prediction (or postdiction, as the case may be).

Here, the output is an entire spectrum. It's observable out to angular momentum moment of a few thousand, which means the output is a few million numbers which form a very specific and characteristic pattern. If any one of those had turned out to be significantly off, inflation would have been fasified. But none of them were - there are a few mild and potentially interesting anomalies, but only a few (again, out of millions).

[sol invictus]

This appears to be a gray area. Initially, inflation was needed to account for observed characteristics of the universe like homogeneity, etc. Later, it was realized that a totally homogeneous era could not lead to the structure currently observed --- some inhomogeneity was needed.

Actually that was realized immediately, not later.

As I recall, quantum fluctuations were then presented as the likely cause of the primordial lumpiness leading to galaxy formation, etc. Then, a search for inhomogeneities in the CMB ensued -- and were found.

Right - but it wasn't just that inhomogeneities were found. A few million data points were collected by satellite, and they matched the predictions extremely well. This was one of the most precise and impressive achievements in the entire field of astrophysics, by the way. It catapulted cosmology into the status of "precision science".


Would there not have to be quantum fluctuations anyway, for galaxies to form, with or without inflation?

No. Quantum fluctuations can only seed structure if there is an event horizon, and that happens only when the expansion is accelerating (which means some variety of inflation).

Are there not other possible explanations for the CMB and its irregularities? It seems that MM's view that aspects of inflation theory are "postdicted" might have some merit.

I don't see any connection between those two sentences.

Sure, there are other possible explanations. None of them work very well at all, though - they're all much more complicated. As for postdicted, I'm befuddled how you can regard a precise prediction for the shape of the spectrum made at least 7 years before the data was available as a "post"-diction.

[sol invictus]

I suppose it's 'possible' to "predict" some some features based purely on mathematical models, but typically, most "predictions' are based upon something that is learned from active experimentation, not simply a mathematical model.

That's not true at all. In all types of physics one uses some experimental input plus certain basic principles and experience to build a mathematical model, and then makes predictions with the model that are then tested. But of course it's the model that makes the predictions. You can't make predictions with experimental results, except perhaps about an absolutely identical experiment - and that wouldn't be interesting. The only way to make predictions is with a model, and in physics the models are mathematical.

The top quark is an excellent example, by the way.

[Perpetual Student]

Actually that was realized immediately, not later.

OK

Right - but it wasn't just that inhomogeneities were found. A few million data points were collected by satellite, and they matched the predictions extremely well. This was one of the most precise and impressive achievements in the entire field of astrophysics, by the way. It catapulted cosmology into the status of "precision science".

Thanks for that clarification and additional insight.

No. Quantum fluctuations can only seed structure if there is an event horizon, and that happens only when the expansion is accelerating (which means some variety of inflation).

Unfortunately, I don't understand QM well enough to follow that but I must accept that as a valid point, unless someone else can refute it.

I don't see any connection between those two sentences.

Sorry, I guess there wasn't any connection. See my comments below.

Sure, there are other possible explanations. None of them work very well at all, though - they're all much more complicated. As for postdicted, I'm befuddled how you can regard a precise prediction for the shape of the spectrum made at least 7 years before the data was available as a "post"-diction.

Let me try this rather fuzzy explanation. Over the years, as I followed the development of inflation theory in periodicals like Scientific American, there appeared to be some ad hoc tag-ons to inflation theory in the wake of new astronomical observations. My feeling is based on the historical context as things unfolded at the time, but I cannot recall enough details to demonstrate my point. I simply have no way of now reconstructing the sequence of observations and theoretical modifications of inflation to document that there were times when new developments appeared to be "postdicted."
In any case, I do continue to accept inflation theory, but not with any sense of certainty.

[DeiRenDopa]

I suppose it's 'possible' to "predict" some some features based purely on mathematical models, but typically, most "predictions' are based upon something that is learned from active experimentation, not simply a mathematical model.That's not true at all. In all types of physics one uses some experimental input plus certain basic principles and experience to build a mathematical model, and then makes predictions with the model that are then tested. But of course it's the model that makes the predictions. You can't make predictions with experimental results, except perhaps about an absolutely identical experiment - and that wouldn't be interesting. The only way to make predictions is with a model, and in physics the models are mathematical.

The top quark is an excellent example, by the way.
Here's a quite different kind of example ...

... the Hulse-Taylor pulsar, and gravitational wave radiation.

With GR, and a model (a pair of 'point' masses in orbit around their mutual centre of mass) one can make certain predictions (rate of decay of the orbits); plug some numbers in (masses, distance between them) and an eminently testable hypothesis falls out (the observed pulses from a binary pulsar will behave {like this} when plotted against time).

No experimental results to be found anywhere ... (oh, and Hulse and Taylor got an all-expenses paid trip to Stockholm).

[sol invictus]

Let me try this rather fuzzy explanation. Over the years, as I followed the development of inflation theory in periodicals like Scientific American, there appeared to be some ad hoc tag-ons to inflation theory in the wake of new astronomical observations.

Well, that's not an entirely unfair criticism. As I mentioned earlier, there are many different inflation models, and there's quite a lot of room to adjust the pre/post-dictions - particularly if you're willing to add ingredients and make the model more complicated. But there are certain features and predictions they all share, and those were well-understood long before the relevant observations were made.

It's very much like quantum field theory. There are infinitely many QFTs, and only one that describes the standard model of particle physics. They all have certain features in common, and physicists were fairly certain particle physics was described by a QFT long before they knew which one it was.

In fact it took quite a long time and lots of experimental input before the correct theory (SU(3)xSU(2)xU(1) with the right matter content) could be identified. It has 25 or so parameters which must be fixed with data. Once that's done, however, it makes lots and lots of predictions, a huge number of which have since been verified (and a few falsified, and the model adjusted).

Similarly there are lots of inflation theories, particularly if you allow them to be as complex as the standard model. We don't currently have the data to nail down which one is correct, but we do have enough to be quite confident that at least one is.

And remember - nature couldn't care less whether we first discover the correct theory and then predict the data, or first find the data and then discover the correct theory. A theory is either correct or not; pre- versus post-diction is a human distinction.

[Zeuzzz]

I think everyone needs to chill. There no point getting personal. This thread has been full of emotive undertones (more-so at the beginning). Fact is that there are a lot of alternative theories out there, and its not a matter of one being the *truth* and all the others crackpot theories made up by *creationists* or [insert stereotype here]. When you put faith in a theory being truth and get religously attatched to it by thinking its beyond reproach from all other theories, your no longer thinking scientifically, but religously.

Theres some good material in this thread. Lets not forget people, multiple theories can be correct at the same time, no matter how different they are. Finding out which theory matches the evidence and data is what should be being done, something called the scientific method. Of which there have been glimmers of in this thread.

I'm not gonna get fully involved either way. Infact I dont spend much time online at all at the moment, real life issues are pressing.

Argue on, and keep it in good faith peeps.

Isn't science wonderful? :)

[Michael Mozina]

Oops, missed it. What they're saying is that they know that a flat spectrum with amplitude around 10^-5 would roughly fit data. But it's very rough, because at the time no precise data was available - and didn't become available until 20 years later.

Typical inflation models, as I've told you, have 1 or 2 parameters, 1 or 2 numbers that must be put in. As with any scientific theory, you use 1 or 2 numbers from data to fix those (in this case, 10^-5 as the overall amplitude). Everything else you get out is a prediction (or postdiction, as the case may be).

Here, the output is an entire spectrum. It's observable out to angular momentum moment of a few thousand, which means the output is a few million numbers which form a very specific and characteristic pattern. If any one of those had turned out to be significantly off, inflation would have been fasified. But none of them were - there are a few mild and potentially interesting anomalies, but only a few (again, out of millions).

My problem with that logic is this: If I already have a number of key "rough" observations from several different wavelengths in the spectrum and I "assume/figure out" that there is a discernible pattern in that data, I can then create a formula to fit that basic pattern.

Unless there really isn't a pattern, my formula, rough as it may be, will still be likely to apply quite well to the later (more refined) measurements. The pattern itself is still "postdicted" from the rough (earlier) observations and the mathematical pattern was still worked out from observation, not from actual "prediction". Unless the postdicted pattern that I come up with is simply wrong, it's going to apply pretty well to later and better measurements. The only thing that is likely to be modified a bit by later, more accurate measurements are the 'variables' but the mathematical pattern was still a postdicted fit.

[Michael Mozina]

Here's a quite different kind of example ...

Oh my goodness. I already conceded in my original post (the part you can't see because you're ignoring me and he cut out that part of my post) that there were exceptions to that rule. You're preaching to the choir.

[Perpetual Student]

And remember - nature couldn't care less whether we first discover the correct theory and then predict the data, or first find the data and then discover the correct theory. A theory is either correct or not; pre- versus post-diction is a human distinction.

Thanks. Perhaps that's the ultimate key. We have a theory; we have matching observations. If no other theory fits the observations (and until one does) we go with what we have.

[Michael Mozina]

And remember - nature couldn't care less whether we first discover the correct theory and then predict the data, or first find the data and then discover the correct theory. A theory is either correct or not; pre- versus post-diction is a human distinction.

I'd be fine with that concept if we could actually demonstrate that inflation is real in a standard test with control mechanisms. As it stands, we're postdicting a fit with an "imaginary" entity that presumably no longer exists and can *never* be verified or falsified in any conventional test with a control mechanism. As long as we're willing to keep modifying inflation theory to fit any and all new observations, it becomes a form of 'dogma' that defies any kind of falsification processes. At that point there is no longer any empirical distinction between science and religion.

[sol invictus]

My problem with that logic is this: If I already have a number of key "rough" observations from several different wavelengths in the spectrum and I "assume/figure out" that there is a discernible pattern in that data, I can then create a formula to fit that basic pattern.

In some cases, perhaps. But that couldn't have happened here. Look at the spectrum. (http://upload.wikimedia.org/wikipedia/commons/1/16/PowerSpectrumExt.svg)

All that was known of that in 1996 (I think, perhaps someone else can cofirm) is the extreme left-hand part of it, stopping well before the first peak at perhaps l~50 (that's the numbers on the horizontal axis) and with large error bars. You tell me - given that much, could you fill in the rest, including relative heights of peaks, their spacing, etc.? Obviously not - and if you look at those papers, you'll see that that isn't at all what happened. Instead, the spectrum was predicted from the model.

I As long as we're willing to keep modifying inflation theory to fit any and all new observations, it becomes a form of 'dogma' that defies any kind of falsification processes. At that point there is no longer any empirical distinction between science and religion.

That's utter nonsense: the progress of science is nothing other than modifying theories to fit new observations. But I'm tired of going around in circles on that, so I'm not going to respond further.

[LibraryLady]

I am the third moderator to step in here. I have sent 28 posts to AAH, all of them off topic. Anyone derailing from here on in risks infraction. Behave.

[DeiRenDopa]

What? Why?

It's true that it was known in the early 1980s that a roughly flat primordial spectrum over some range of scales would probably be consistent with observations, but that's it (and that's why those guys were excited about their results). But inflation predicted something much more specific, only the first rough version of which is in those 1982 papers. By 1996 paper there were many details (like the acoustic peaks), none of which were observed until years later.This appears to be a gray area. Initially, inflation was needed to account for observed characteristics of the universe like homogeneity, etc. Later, it was realized that a totally homogeneous era could not lead to the structure currently observed --- some inhomogeneity was needed. As I recall, quantum fluctuations were then presented as the likely cause of the primordial lumpiness leading to galaxy formation, etc. Then, a search for inhomogeneities in the CMB ensued -- and were found.
Would there not have to be quantum fluctuations anyway, for galaxies to form, with or without inflation? Are there not other possible explanations for the CMB and its irregularities? It seems that MM's view that aspects of inflation theory are "postdicted" might have some merit.
I'd like to introduce an example from astronomy that shines a bright light on the "predicted/post-dicted" distinction; I think the only reasonable conclusion one can draw from this example is that such a distinction is pretty close to meaningless, and that if you do wish to try to keep it, you would need to pay extraordinary attention to detail.

Consider "dark matter".

Zwicky introduced the term, in the 1930s, to account for an apparent inconsistency in an analysis he did of the data he obtained on a rich galaxy cluster (Coma). At the time, Zwicky had no reason to introduce 'non-baryonic' as a modifier, nor 'cold'; indeed, it is unlikely either *could* have been applied at the time!

Not long afterwards (or possibly before), Jan Oort (yes, of Oort cloud fame) published evidence for the existence of dark matter in the local region of the Milky Way (i.e. within a few hundred pc of sol); several decades later re-analysis together with far more extensive data showed his conclusion was in error.

In the late 1960s, Rubin (and colleagues) published studies of the rotation curves of some nearby normal spiral galaxies, concluding that these galaxies are embedded in a halo of dark matter.

It took another ~25+ years for compact massive halo objects (MACHOs) to be ruled out as the primary component of this inferred massive halo; sometime around then dark matter began to be seriously considered as being non-baryonic (and cold).

Sometime after the first decent x-ray band data on rich galactic clusters became available, the existence of an essentially thermal, hot, diffuse IGM was confirmed; the estimated mass of such was, and still is, considerably greater than the total estimated mass of all the galaxies in such clusters, dark matter halos included. However, the estimated total mass of such clusters exceeded (and still exceeds) that of the IGM by a factor of ~5.

Along the way, and completely independently, cosmological research was converging on an estimate of the average mass density of the universe being ~one-fifth of the critical density; of this mass, several lines of independent evidence strongly suggested that only ~one-fifth was baryonic.

(the actual history is much, much, much more intricate than I have outlined above).

So, to cut to the chase: non-baryonic cold dark matter ("CDM"), as a theory, is extraordinarily successful ... it accounts for millions of independent observations, across the full range of the electromagnetic spectrum, and of an extraordinary range of objects (from dwarf galaxies to normal galaxies to giant galaxies to galaxy groups to galaxy clusters to the universe as a whole). In the multi-decade history of the study of CDM (to be anachronistic for several decades), there have been several 'crises', many curiosities and anomalies, a great deal of refinement and revision, hundreds and hundreds of predictions and post-dictions, etc, etc, etc, etc.

And I haven't even introduced an independent line of research: indications from particle physics of the existence of an entire class of particles hithertofore unseen, the properties of which could well match those of CDM (should CDM be composed of particles).

I have read MM's posts on this topic (there are dozens, if not hundreds), and like si I find that his characterisation of astronomy is grotesque, and his views on 'controlled experiments' etc riddled with misconceptions, internal inconsistencies, etc.

[Perpetual Student]

DeiRenDopa:

Thank you for the above historical summary of dark matter. I understand that you necessarily omitted countless details; nevertheless, it was very helpful.
The sad reality is that it is difficult for a layman to access all the context you just provided.
As I mentioned above, I have been following developments in cosmology for many years now (about 50), but obviously (and sadly) the significance of many details and interlinking of concepts have escaped my grasp.

[DeiRenDopa]

PS, for a relatively brief, non-technical overview, I recommend "In Search of Dark Matter", by Ken Freeman and Geoff McNamara (2006, Springer/Praxis; ISBN: 0-387-27616-5). Freeman, who must be close to retirement by now, is a professional astronomer who has been working on DM for just about his whole (professional) life, developed at least one of the observational tools used to test various DM hypotheses (i.e. PNe in the outskirts of galaxies), and has authored several hundred papers (not all as sole, or even lead, author of course!). There are other, popular-level, books on the topic, but this is the best that I've read.

[Michael Mozina]

DeiRenDopa:

Thank you for the above historical summary of dark matter. I understand that you necessarily omitted countless details; nevertheless, it was very helpful.
The sad reality is that it is difficult for a layman to access all the context you just provided.
As I mentioned above, I have been following developments in cosmology for many years now (about 50), but obviously (and sadly) the significance of many details and interlinking of concepts have escaped my grasp.

FYI, there are new signs that the 'mass estimation techniques' of standard theories will require some revision because they fail to account for some of even the most visible material that is located inside various galaxies:

http://www.sciencedaily.com/releases/2009/08/090819145846.htm

The effects are particularly important in parts of the universe where stars are spread out over a larger volume -- the rural Africa of the cosmos. There could be about four times as many stars in these regions than previously estimated.

"Especially in these galaxies that seem small and piddling, there can be a lot more mass in lower mass stars than we had previously expected from what we could see from the brightest, youngest stars," Meurer said. "But we can now reduce these errors using satellites like the Galaxy Evolution Explorer."

Emphasis mine.

[Reality Check]

FYI, there are new signs that the 'mass estimation techniques' of standard theories will require some revision because they fail to account for some of even the most visible material that is located inside various galaxies:

http://www.sciencedaily.com/releases/2009/08/090819145846.htm

Emphasis mine.
Interesting article on how one technique for measuring the mass of galaxies is being refined.

[Michael Mozina]

Interesting article on how one technique for measuring the mass of galaxies is being refined.

Indeed. One wonders about the value of current estimation techniques if they underestimate the number of highly visible stars by a factor of four. The notion of "dark" seems to apply not only to non baryonic matter, but anything under a specific physical size, including even smaller sized suns. It makes the whole notion of SUSY theory that much less plausible, and certainly that much less necessary IMO. They don't even seem to have a good handle yet on the amount of highly visible baryonic material in a galaxy, so why would I believe there is any need for non baryonic forms of matter to explain 'missing mass'?

[Reality Check]

Indeed. One wonders about the value of current estimation techniques if they underestimate the number of highly visible stars by a factor of four. The notion of "dark" seems to apply not only to non baryonic matter, but anything under a specific physical size, including even smaller sized suns. It makes the whole notion of SUSY theory that much less plausible, and certainly that much less necessary IMO. They don't even seem to have a good handle yet on the amount of highly visible baryonic material in a galaxy, so why would I believe there is any need for non baryonic forms of matter to explain 'missing mass'?
You misread the article.
The point is that these stars are not "highly visible" and so their numbers were estimated in the past. Current observation techniques have revealed that in some galaxies the smaller mass stars may be miscounted by a factor of 4.


This belief, based on years of research, has been tipped on its side with new data from NASA's Galaxy Evolution Explorer. The ultraviolet telescope has found proof that small stars come in even bigger bundles than previously believed; for example, in some places in the cosmos, about 2,000 low-mass stars may form for each massive star. The little stars were there all along but masked by massive, brighter stars.
....
"Especially in these galaxies that seem small and piddling, there can be a lot more mass in lower mass stars than we had previously expected from what we could see from the brightest, youngest stars," Meurer said. "But we can now reduce these errors using satellites like the Galaxy Evolution Explorer."

(Emphasis mine)

They do have a "good handle" on the mass of the baryonic material in a galaxy. This new observation will allow more accurate estimates of galaxy masses.
A real astronomer could tell us the real error limit in galaxy mass calculations (50%?)

ETA: The actual journal article looks like "Evidence for a Nonuniform Initial Mass Function in the Local Universe (http://www.iop.org/EJ/abstract/0004-637X/695/1/765)".

[Michael Mozina]

You misread the article.
The point is that these stars are not "highly visible" and so their numbers were estimated in the past. Current observation techniques have revealed that in some galaxies the smaller mass stars may be miscounted by a factor of 4.

What you're essentially saying is that "previous" observations (at the visible spectrum) were incapable of picking out even highly visible forms of baryonic material, whereas more modern instruments are in fact capable of noticing this omission. What you seem to be ignoring is the fact that current techniques don't account for these modern observations, at least not yet.

(Emphasis mine)

They do have a "good handle" on the mass of the baryonic material in a galaxy. This new observation will allow more accurate estimates of galaxy masses.
A real astronomer could tell us the real error limit in galaxy mass calculations (50%?)

That sounds rather like an underestimate rather than a real number IMO, particularly if they underestimate the number of stars by a factor of four. The point here is that our current technologies haven't even been applied to our mass estimation techniques yet, so why should anyone have 'great faith' that any material is located in SUSY particles if we can't even accurately measure (or haven't accurately factored in) the amount of highly visible stars in a galaxy?

[Reality Check]

What you're essentially saying is that "previous" observations (at the visible spectrum) were incapable of picking out even highly visible forms of baryonic material, whereas more modern instruments are in fact capable of noticing this omission. What you seem to be ignoring is the fact that current techniques don't account for these modern observations, at least not yet.

That is right (but I would say throughout the spectrum rather than just visible). That is what the last paragraph of the article states.


That sounds rather like an underestimate rather than a real number IMO, particularly if they underestimate the number of stars by a factor of four. The point here is that our current technologies haven't even been applied to our mass estimation techniques yet, so why should anyone have 'great faith' that any material is located in SUSY particles if we can't even accurately measure (or haven't accurately factored in) the amount of highly visible stars in a galaxy?
It also sounds like a underestimate to me.

As as already been stated to you on many occassions:

We can be confident that dark matter is non baryonic matter beacase
The mass estimates are not out by the factors that are needed to account for dark matter.
Baryonic dark matter has been looked for and not found (MACHOs (http://en.wikipedia.org/wiki/Massive_compact_halo_object)).
Dark matter acts as if it weakly interacts electromagnetcally (i.e. is non baryonic):
NASA Finds Direct Proof of Dark Matter (http://chandra.harvard.edu/photo/2006/1e0657/) (another observation (http://hubblesite.org/newscenter/archive/releases/2008/32/))
ETA:
Make this the three observations aready cited to you in another thread (http://forums.randi.org/showpost.php?p=4934195&postcount=2575): 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))

[Michael Mozina]

That is right (but I would say throughout the spectrum rather than just visible). That is what the last paragraph of the article states.

That really tends to blur the term "dark" doesn't it? I mean it may be "dark" in the visible spectrum relative to our current technologies, but it's not "dark" on every spectrum.


We can be confident that dark matter is non baryonic matter beacase[LIST=1]
The mass estimates are not out by the factors that are needed to account for dark matter.

How do you know that? They evidently have underestimated the number of stars in a galaxy by at least a factor of four. My "guess" is that is a relatively 'conservative" number as well.

Baryonic dark matter has been looked for and not found

They just found a bunch of baryonic matter! I don't think you like the implications of this article/paper, but it's pretty clear. We haven't accurately estimated the amount of even the number of stars in a galaxy, so the whole notion that non baryonic forms of matter are required to explain "missing mass" is highly suspect. We could and evidently are simply grossly underestimating the amount of normal material in a galaxy. Period.

[Reality Check]

How do you know that? They evidently have underestimated the number of stars in a galaxy by at least a factor of four. My "guess" is that is a relatively 'conservative" number as well.
They have just found a bunch os baryonic matter - just not enough. They need factors of 100's of unmeasured stars.

The stars in question are not "dark" matter. They are normal visible matter that is just hard to see in the visible spectum because of the glare from brighter stars and so you have to look in the non-visible spectrum:
Evidence for a Nonuniform Initial Mass Function in the Local Universe (http://www.iop.org/EJ/abstract/0004-637X/695/1/765)

Many of the results in modern astrophysics rest on the notion that the initial mass function (IMF) is universal. Our observations of a sample of H I selected galaxies in the light of Hα and the far-ultraviolet (FUV) challenge this result. The extinction-corrected flux ratio F Hα/f FUV from these two tracers of star formation shows strong correlations with the surface brightness in Hα and the R band: low surface brightness (LSB) galaxies have lower F Hα/f FUV ratios compared to high surface brightness galaxies as well as compared to expectations from equilibrium models of constant star formation rate (SFR) using commonly favored IMF parameters. Weaker but significant correlations of F Hα/f FUV with luminosity, rotational velocity, and dynamical mass as well as a systematic trend with morphology, are found. The correlated variations of F Hα/f FUV with other global parameters are thus part of the larger family of galaxy scaling relations. The F Hα/f FUV correlations cannot be due to residual extinction correction errors, while systematic variations in the star formation history (SFH) cannot explain the trends with both Hα and R surface brightness nor with other global properties. The possibility that LSB galaxies have a higher escape fraction of ionizing photons seems inconsistent with their high gas fraction, and observations of color-magnitude diagrams (CMDs) of a few systems which indicate a real deficit of O stars. The most plausible explanation for the correlations is the systematic variations of the upper mass limit http://ej.iop.org/images/0004-637X/695/1/765/apj299976ieqn1.gif and/or the slope γ which define the upper end of the IMF. We outline a scenario of pressure driving the correlations by setting the efficiency of the formation of the dense star clusters where the highest mass stars preferentially form. Our results imply that the SFR measured in a galaxy is highly sensitive to the tracer used in the measurement. A nonuniversal IMF would also call into question the interpretation of metal abundance patterns in dwarf galaxies as well as SFHs derived from CMDs.


The impact of this observation on dark matter is minor. The evidence that dark matter is non baryonic matter is strong. The amount of baryonic matter is not increaed enough to account for the amount of dark matter that is observed, e.g. by galactic lensing.

[tuc0]

Great tags on this thread! Recent Data shows that if the Big Bag is full of holes stuff (also known as matter) will keep falling out. :D

[DeiRenDopa]

Indeed. One wonders about the value of current estimation techniques if they underestimate the number of highly visible stars by a factor of four. The notion of "dark" seems to apply not only to non baryonic matter, but anything under a specific physical size, including even smaller sized suns. It makes the whole notion of SUSY theory that much less plausible, and certainly that much less necessary IMO. They don't even seem to have a good handle yet on the amount of highly visible baryonic material in a galaxy, so why would I believe there is any need for non baryonic forms of matter to explain 'missing mass'?You misread the article.
The point is that these stars are not "highly visible" and so their numbers were estimated in the past. Current observation techniques have revealed that in some galaxies the smaller mass stars may be miscounted by a factor of 4.

This belief, based on years of research, has been tipped on its side with new data from NASA's Galaxy Evolution Explorer. The ultraviolet telescope has found proof that small stars come in even bigger bundles than previously believed; for example, in some places in the cosmos, about 2,000 low-mass stars may form for each massive star. The little stars were there all along but masked by massive, brighter stars.
....
"Especially in these galaxies that seem small and piddling, there can be a lot more mass in lower mass stars than we had previously expected from what we could see from the brightest, youngest stars," Meurer said. "But we can now reduce these errors using satellites like the Galaxy Evolution Explorer."
(Emphasis mine)

They do have a "good handle" on the mass of the baryonic material in a galaxy. This new observation will allow more accurate estimates of galaxy masses.
A real astronomer could tell us the real error limit in galaxy mass calculations (50%?)

ETA: The actual journal article looks like "Evidence for a Nonuniform Initial Mass Function in the Local Universe (http://www.iop.org/EJ/abstract/0004-637X/695/1/765)".
Yes, that does seem to be the paper on which the PR is based.

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).

[DeiRenDopa]

What you're essentially saying is that "previous" observations (at the visible spectrum) were incapable of picking out even highly visible forms of baryonic material, whereas more modern instruments are in fact capable of noticing this omission. What you seem to be ignoring is the fact that current techniques don't account for these modern observations, at least not yet.That is right (but I would say throughout the spectrum rather than just visible). That is what the last paragraph of the article states.
I don't know how to even begin addressing this ...

... but here goes.

The relationship between a star's mass and its electromagnetic output (both total energy output and SED, spectral energy distribution) is now quite well understood, and observations of individual stars in a particular galaxy (or part thereof) can use this well-established relationship for a variety of purposes.

One such purpose is to estimate the initial mass function of stars; the distribution of stars, by mass (or luminosity) at birth. Such research has been going on for decades, and consistent results have been obtained for stars in star clusters; however, the extent to which the observed (star cluster) IMF is universal is not well-constrained.

Turning to observations of galaxies.

Except for those in the Local Group, and except for instruments such as the HST, individual stars in galaxies cannot be 'resolved' (caveat: novae and supernovae are exceptions). So the techniques used to estimate the stellar content of these galaxies rely upon observations other than the detection of individual stars (there are several such). What this paper says is that proxies for the number of O stars and the number of B stars (one proxy for each) can be used to estimate the extent to which the top part of the IMF varies between galaxies. This is quite difficult to do - the paper spends many pages discussing the various systematic effects the authors identified and tried to control for, for example - but they make a good case that there is a variation. They also point out that their finding is consistent with what several others have found, using completely different techniques.

Perhaps the most exciting implication of the finding is the possibility of getting a better handle on the extent to which star formation is dependent on environment!

That sounds rather like an underestimate rather than a real number IMO, particularly if they underestimate the number of stars by a factor of four. The point here is that our current technologies haven't even been applied to our mass estimation techniques yet, so why should anyone have 'great faith' that any material is located in SUSY particles if we can't even accurately measure (or haven't accurately factored in) the amount of highly visible stars in a galaxy?

It also sounds like a underestimate to me.

As as already been stated to you on many occassions:

We can be confident that dark matter is non baryonic matter beacase
The mass estimates are not out by the factors that are needed to account for dark matter.
Baryonic dark matter has been looked for and not found (MACHOs (http://en.wikipedia.org/wiki/Massive_compact_halo_object)).
Dark matter acts as if it weakly interacts electromagnetcally (i.e. is non baryonic):
NASA Finds Direct Proof of Dark Matter (http://chandra.harvard.edu/photo/2006/1e0657/) (another observation (http://hubblesite.org/newscenter/archive/releases/2008/32/))
ETA:
Make this the three observations aready cited to you in another thread (http://forums.randi.org/showpost.php?p=4934195&postcount=2575): 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))
There's so much confusion here!

First, though, the application of an IMF to estimate a galaxy's mass is relatively restricted ... where the IMF is used is in making estimates of the mass-to-light ration (M/L), expressed in sols; specifically, the observed luminosity is used to derive an estimate of the total stellar content, the mass is estimated using techniques that (typically) have nothing to do with the IMF.

Second, studies of different kinds of galaxies (LSB, BCD, dSp, E, ...) tend to give consistent results, wrt the total mass, M/L, and so on.

Third, most of the mass in the observable universe seems to reside in the IGM of clusters of galaxies, not the galaxies themselves, so a change in the estimated mass of the stars in some kinds of galaxies has essentially no impact on larger scales.

I think I'll stop here; I'm probably only making matters more confusing ...

[DeiRenDopa]

How do you know that? They evidently have underestimated the number of stars in a galaxy by at least a factor of four. My "guess" is that is a relatively 'conservative" number as well.They have just found a bunch os baryonic matter - just not enough. They need factors of 100's of unmeasured stars.
We are now so far from what the paper says that I see no point in commenting ... except to say that if anyone is interested, I'd be happy to walk them through the paper, paying particular attention to what it actually says (and not what implications you think you can read into it).

In a nutshell, the paper's direct implications have to do with estimating SFRs (star formation rates) in one class of rather poorly understood galaxies (LSBs) ... and the authors discuss this in Section 6.3; the extent to which variations in the top end of the IMF between galaxies impacts estimates of the baryonic content of those galaxies is not discussed in the paper (and rightly so too).


[...]


The impact of this observation on dark matter is minor. The evidence that dark matter is non baryonic matter is strong. The amount of baryonic matter is not increaed enough to account for the amount of dark matter that is observed, e.g. by galactic lensing.
Indeed.

One of the extraordinary things about CDM is the breadth of its explanatory power.

[Michael Mozina]

The relationship between a star's mass and its electromagnetic output (both total energy output and SED, spectral energy distribution) is now quite well understood,....

I'm sorry, but when you say this kind of thing after that kind of revelation, it's really hard to take you seriously anymore.

http://www.spaceref.com/news/viewpr.html?pid=25444

Dr Driver said, "You can't get more energy out than you put in so we knew something was very wrong. Even so, the scale of the dust problem has come as a shock appears that galaxies generate twice as much starlight as previously thought."

The team combined an innovative new model of the dust distribution in galaxies developed by Dr Cristina Popescu of the University of Central Lancashire and Prof Richard Tuffs of the Max Plank Institute for Nuclear Physics, with data from the Millennium Galaxy Catalogue, a state-of-the-art high resolution catalogue of 10,000 galaxies assembled by Driver and his team using the Isaac Newton Telescope on La Palma among others.

Using the new model, the astronomers could calculate precisely the fraction of starlight blocked by the dust. The key test that the new model passed was whether the energy of the absorbed starlight equated to that detected from the glowing dust.

"The equation balanced perfectly", said Dr Cristina Popescu, "and for the first time we have a total understanding of the energy output of the Universe over a monumental wavelength range."

"The results demonstrate very clearly that interstellar dust grains have a devastating effect on our measurements of the energy output from even nearby galaxies" says Prof Richard Tuffs, "with the new calibrated model in hand we can now calculate precisely the fraction of starlight blocked by the dust."

In just the last year and a half, we have discovered that the galaxies are shining twice as brightly as we once thought (way more starlight), the number of small mass stars is four times what we first believed, we're still "missing" most of the mass of a galaxy, and you now want me to believe that we have these things all figured out and everything is 'well understood'. Please. Your statements simply don't jive with reality.

I have no doubt that we *THOUGHT* these relationships were well understood, but clearly they are not as simple as we believed, and a lot of that 'missing mass' isn't found in "dark matter', but in the form of actual stars in the galaxy. How exactly did you expect the stars to shine twice and brightly without increasing the mass of the galaxy?

It seems to me that if we haven't correctly identified even something as visually obvious as a star, or the amount of starlight coming from a galaxy, then there is really no reason to believe that our mass estimation techniques are currently worth the paper they are printed on. A quick glance at the lensing data verifies that we have grossly underestimated the standard mass of a galaxy and these two papers explain at least part of the problems with our mass estimation techniques. They are based on *MANY* different assumptions, some of which are evidently way off.

[Skwinty]

We are now so far from what the paper says that I see no point in commenting ... except to say that if anyone is interested, I'd be happy to walk them through the paper, paying particular attention to what it actually says (and not what implications you think you can read into it).


Yes please.

In a nutshell, the paper's direct implications have to do with estimating SFRs (star formation rates) in one class of rather poorly understood galaxies (LSBs) ... and the authors discuss this in Section 6.3; the extent to which variations in the top end of the IMF between galaxies impacts estimates of the baryonic content of those galaxies is not discussed in the paper (and rightly so too).


Please expand these two bolded acronyms. Thanks for the illuminating posts.

[DeiRenDopa]

LSB = low surface brightness (galaxies)
IMF = initial mass function.

Do you have a copy of the paper to hand Skwinty? It doesn't have to be what was actually published in ApJ, arXiv:0902.0384v2 will do.

If so, let's start with the Summary (section 7); if not, please get one (and let me know when you have it).

[Skwinty]

LSB = low surface brightness (galaxies)
IMF = initial mass function.



Thanks, now that I have the correct paper, I can see my question was rather shortsighted.

[DeiRenDopa]

Thanks, now that I have the correct paper, I can see my question was rather shortsighted.
No worries.

Why not take some time to read, or at least skim, the paper first? As I said, perhaps a good way to go through it is to go through the Summary, point by point; however, you may get more understanding by asking questions directly (your choice! :) ).

[Skwinty]

Why not take some time to read, or at least skim, the paper first? .

Thanks, I will read the paper and then kick off by asking some questions.
I am at home now, but doing some work as I have a deadline to meet.
I will be ready to start later tonight or tomorrow.

[Perpetual Student]

PS, for a relatively brief, non-technical overview, I recommend "In Search of Dark Matter", by Ken Freeman and Geoff McNamara (2006, Springer/Praxis; ISBN: 0-387-27616-5). Freeman, who must be close to retirement by now, is a professional astronomer who has been working on DM for just about his whole (professional) life, developed at least one of the observational tools used to test various DM hypotheses (i.e. PNe in the outskirts of galaxies), and has authored several hundred papers (not all as sole, or even lead, author of course!). There are other, popular-level, books on the topic, but this is the best that I've read.

Thanks for that. While I do find that MM's objections to standard cosmology far fetched, he does occasionally make some good points. When I see statements like:

Current interpretations of astronomical observations indicate that the age of the Universe is 13.73 (± 0.12) billion years,[1] and that the diameter of the observable Universe is at least 93 billion light years, or 8.80 × 1026 metres.
FROM: link (http://en.wikipedia.org/wiki/Universe)

followed by the discovery that we have this magnitude of error LINK (http://www.sciencedaily.com/releases/2009/08/090819145846.htm) in our observations, I become quite perplexed. There appears to be quite a bit of hubris in a number like 13.75 +/- .12 years. If we do not have an accurate reading of "small stars" to the degree of a four-fold error, how can we come by such an exact estimate for the age of the universe.

[Monketey Ghost]

*snip*
Isn't science wonderful? :)

Yes! Especially when it's actual science!

[DeiRenDopa]

Thanks for that. While I do find that MM's objections to standard cosmology far fetched, he does occasionally make some good points. When I see statements like:


FROM: link (http://en.wikipedia.org/wiki/Universe)

followed by the discovery that we have this magnitude of error LINK (http://www.sciencedaily.com/releases/2009/08/090819145846.htm) in our observations, I become quite perplexed. There appears to be quite a bit of hubris in a number like 13.75 +/- .12 years. If we do not have an accurate reading of "small stars" to the degree of a four-fold error, how can we come by such an exact estimate for the age of the universe.
I'm not sure I follow PS; the estimated age of the universe owes essentially nothing to what's in the paper that PR you provide a link to is based on (see my earlier posts) ... perhaps it would be of interest to you if I outlined how the age of the observable universe is estimated?

Or did you have some other question?

[Perpetual Student]

I'm not sure I follow PS; the estimated age of the universe owes essentially nothing to what's in the paper that PR you provide a link to is based on (see my earlier posts) ... perhaps it would be of interest to you if I outlined how the age of the observable universe is estimated?

Or did you have some other question?

Sorry that my point was not clear. Well, the error in the estimate for "small stars" causes one to speculate about how many other errors there might be in our current assumptions about astronomical phenomena -- it simply causes a lack of confidence in the whole process of making astronomical estimates. The extrapolations to the big bang depend on many current estimates of the universe as we currently see it. Is that not true? Perhaps we get a pass on the number of "small stars" as it effects estimates of the age of the universe, but that cannot be true of every estimate we make about astronomical phenomena.

Yes I would very much like to see an outline of how the age of the universe is estimated to such an astonishingly precise number.

[QED]

Does anyone know where I can find figures on the distribution of baryonic matter? Ie. what percentage of all baryonic matter makes up stars? What percentage the IGM? Planets and other small bodies and hard to detect bodies etc?

I couldn't find these figures, I tried various terms but all that kept popping up is the percentage of baryonic matter in the universe (compared to non-baryonic matter and dark energy). Not how the baryonic mass is distribution among its constituents.

ETA:
Well, the error in the estimate for "small stars" causes one to speculate about how many other errors there might be in our current assumptions about astronomical phenomena -- it simply causes a lack of confidence in the whole process of making astronomical estimates.

DeiRenDopa is certainly more qualified than I am to answer your question about the big bang, but I want to throw in one fact that really impressed me when I read up on measuring distances in space.

Astronomers are extremely ingenuous when it comes to finding mutually independent ways to measure the same attribute of something. Since it is THE most important aspect of astronomy to get reliable measurements they try every conceivable way to do it and are in general very tentative. Compared to most other sciences astronomical objects can't be studied in the laboratory, so methodology is essential. Close attention is paid to systematic errors that could corrupt the results and astronomers love to put error bars on everything. :P

So when we are talking about one kind of measurement being off to some decree, there normally are still completely independent ways that show to WHAT DECREE the measurement could potentially be off. Since those mutually independent methods produce results on the same order of magnitude.

I like to compare this to geology were many different and independent radiometric dating methods are used to date a rock and while all have quite big error bars, they together give us a good and reliable estimate on the age. The same is true for astronomy.

[Michael Mozina]

Does anyone know where I can find figures on the distribution of baryonic matter? Ie. what percentage of all baryonic matter makes up stars? What percentage the IGM? Planets and other small bodies and hard to detect bodies etc?

I couldn't find these figures, I tried various terms but all that kept popping up is the percentage of baryonic matter in the universe (compared to non-baryonic matter and dark energy). Not how the baryonic mass is distribution among its constituents.

When you do get your explanation, make sure the number they come up with includes those recent revelations that galaxies are twice as bright as we realized and there are four times as many stars in a galaxy as we first assumed. :)

[Ziggurat]

Does anyone know where I can find figures on the distribution of baryonic matter? Ie. what percentage of all baryonic matter makes up stars? What percentage the IGM? Planets and other small bodies and hard to detect bodies etc?

I couldn't find these figures, I tried various terms but all that kept popping up is the percentage of baryonic matter in the universe (compared to non-baryonic matter and dark energy). Not how the baryonic mass is distribution among its constituents.

Any object which we can see is primarily baryonic matter - the non-baryonic component being just electrons, which make up a very small mass fraction. That includes planets and other smaller objects. Non-baryonic dark matter interacts weakly, and should not form compact objects.

[ben m]

Does anyone know where I can find figures on the distribution of baryonic matter? Ie. what percentage of all baryonic matter makes up stars? What percentage the IGM? Planets and other small bodies and hard to detect bodies etc?

You're looking for the Cosmic Baryon Budget. The classic paper is Fukugita, Hogan, and Peebles. (I think there's a more-recent paper by some of the same authors.)

http://arxiv.org/abs/astro-ph/9712020

[Michael Mozina]

Thanks for that. While I do find that MM's objections to standard cosmology far fetched, he does occasionally make some good points. When I see statements like:


FROM: link (http://en.wikipedia.org/wiki/Universe)

followed by the discovery that we have this magnitude of error LINK (http://www.sciencedaily.com/releases/2009/08/090819145846.htm) in our observations, I become quite perplexed. There appears to be quite a bit of hubris in a number like 13.75 +/- .12 years. If we do not have an accurate reading of "small stars" to the degree of a four-fold error, how can we come by such an exact estimate for the age of the universe.

Good question. :)

[Michael Mozina]

You're looking for the Cosmic Baryon Budget. The classic paper is Fukugita, Hogan, and Peebles. (I think there's a more-recent paper by some of the same authors.)

http://arxiv.org/abs/astro-ph/9712020

Note that the "classic' paper neither includes the revelation that galaxies are twice as bright as we realized in 1998, or the fact that galaxies have four times as many smaller stars in them than we thought in 1998.

[Dancing David]

Thanks for that. While I do find that MM's objections to standard cosmology far fetched, he does occasionally make some good points. When I see statements like:


FROM: link (http://en.wikipedia.org/wiki/Universe)

followed by the discovery that we have this magnitude of error LINK (http://www.sciencedaily.com/releases/2009/08/090819145846.htm) in our observations, I become quite perplexed. There appears to be quite a bit of hubris in a number like 13.75 +/- .12 years. If we do not have an accurate reading of "small stars" to the degree of a four-fold error, how can we come by such an exact estimate for the age of the universe.

The universe that can be seen is smaller thna the universe that possibly exists?

The determination of the age of the universe is made rather accurately, the Hubble constant gets narrowed every year. But it is based upon the Hubble constant.

This is kind of interesting:
http://hubblesite.org/newscenter/archive/releases/2009/08/

[DeiRenDopa]

Sorry that my point was not clear. Well, the error in the estimate for "small stars" causes one to speculate about how many other errors there might be in our current assumptions about astronomical phenomena -- it simply causes a lack of confidence in the whole process of making astronomical estimates.
First, I invite you to join Skwinty ... download the paper (NOT the PR!), read it, and then ask questions (I'll be happy to try to help you understand the paper, and also show you how misleading the PR is).

Second, every conclusion drawn from astronomical observations comes with estimates of uncertainty. Further, in nearly every case, how the 'error budget' is determined is at least described (and in some cases, it is the sole topic of a string of very long papers!). Then, again in nearly every case, a clear distinction is made between estimated uncertainty due to known, essentially random factors, and estimated uncertainty due to systematic effects.

Systematic effects are the bane of astronomers' lives (or, to some, their primary research topic), and vast amounts of time and effort go into studying them. However, it is a fact of modern life that this 'back story' sells no papers, so you rarely see it (in PRs, popsci articles, etc, etc, etc). One unfortunate consequence is that all kinds of weird ideas start to float around the internet, based on little more than ignorance of estimates of uncertainty in astronomical results (and some folk apparently seek out this sort of thing to the exclusion of everything else).

Bottom line: if you are interested in the degree of confidence that can reasonably be given to any particular astronomical result, I think you have no choice but to roll up your sleeves and learn how the result was obtained, and what those engaged in doing the research have (and have not) already painstakingly taken account of.

OK, I'll climb down now.

The extrapolations to the big bang depend on many current estimates of the universe as we currently see it. Is that not true? Perhaps we get a pass on the number of "small stars" as it effects estimates of the age of the universe, but that cannot be true of every estimate we make about astronomical phenomena.

Yes I would very much like to see an outline of how the age of the universe is estimated to such an astonishingly precise number.
Happy to oblige! :)

First, though, the sources.

This LAMBDA ("Legacy Archive for Microwave Background Data Analysis") webpage (http://lambda.gsfc.nasa.gov/product/map/current/map_bibliography.cfm) is by far the best single source ("Bibliography of WMAP Science Team Publications Five Year Data Scientific Papers"). The single paper you should read is "Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Likelihoods and Parameters from WMAP Data" (third from the bottom). If you haven't already done so, familiarise yourself with the cosmology tutorial on Ned Wright's website (http://www.astro.ucla.edu/~wright/cosmolog.htm); the FAQs include one called "Age of the Universe (http://www.astro.ucla.edu/~wright/age.html)"; I think that should answer your question.

The number you quoted earlier comes from a newspaper (!), but its likely source is a PR from the WMAP team, probably from their Three-Year results; you can learn about how observations of the CMB can be used to estimate the age of the universe from the LAMBDA webpage (above).

[Michael Mozina]

>># The age of the chemical elements.
>># The age of the oldest star clusters.

FYI, these two "measurements" are based upon the 'assumption' that elements do not mass separate (much) in stars. Iron and Nickel presumably somehow stay mixed with hydrogen and helium. If you remove that specific assumption, these particular methods become highly suspect, in fact they become useless.

[DeiRenDopa]

Does anyone know where I can find figures on the distribution of baryonic matter? Ie. what percentage of all baryonic matter makes up stars? What percentage the IGM? Planets and other small bodies and hard to detect bodies etc?

I couldn't find these figures, I tried various terms but all that kept popping up is the percentage of baryonic matter in the universe (compared to non-baryonic matter and dark energy). Not how the baryonic mass is distribution among its constituents.
The paper ben m cited is a good starting place ... though, as he notes, "there's a more-recent paper by some of the same authors" ... indeed; this classic has been cited 735 times (according to ADS)!

This may be what he had in mind: The Cosmic Energy Inventory (http://cdsads.u-strasbg.fr/abs/2004ApJ...616..643F)

If this isn't what you're looking for, just holler ...

ETA:


DeiRenDopa is certainly more qualified than I am to answer your question about the big bang, but I want to throw in one fact that really impressed me when I read up on measuring distances in space.

Astronomers are extremely ingenuous when it comes to finding mutually independent ways to measure the same attribute of something. Since it is THE most important aspect of astronomy to get reliable measurements they try every conceivable way to do it and are in general very tentative. Compared to most other sciences astronomical objects can't be studied in the laboratory, so methodology is essential. Close attention is paid to systematic errors that could corrupt the results and astronomers love to put error bars on everything. :P

So when we are talking about one kind of measurement being off to some decree, there normally are still completely independent ways that show to WHAT DECREE the measurement could potentially be off. Since those mutually independent methods produce results on the same order of magnitude.

I like to compare this to geology were many different and independent radiometric dating methods are used to date a rock and while all have quite big error bars, they together give us a good and reliable estimate on the age. The same is true for astronomy.
Quite.

And it gets much, much worse when the Chinese whispers converts what's in Meurer et al. paper into something like "we do not have an accurate reading of "small stars" to the degree of a four-fold error"! As you can see, above, RC did a sterling job of trying to address MM's wild imagination wrt interpreting the PR (it seems MM did not read the actual paper), but if you are completely blind to the details of what was actually studied, what the scope of the results is, what the uncertainties are, etc, etc, etc it's all too easy to get confused.

[QED]

You're looking for the Cosmic Baryon Budget. The classic paper is Fukugita, Hogan, and Peebles. (I think there's a more-recent paper by some of the same authors.)

http://arxiv.org/abs/astro-ph/9712020
Thanks! That's exactly what I've been looking for. :)

ETA:
The paper ben m cited is a good starting place ... though, as he notes, "there's a more-recent paper by some of the same authors" ... indeed; this classic has been cited 735 times (according to ADS)!

This may be what he had in mind: The Cosmic Energy Inventory
I think it's the right one, thanks!
[...] Our inventory includes the mass densities in the various
states of baryons. This is an updated version of the baryon
budget of Fukugita et al. (1998, hereafter FHP98).Most entries
in this part of the inventory have not changed much in the past
half-decade, while substantial advances in the observational
constraints have considerably reduced the uncertainties. It appears
that most of the baryonic components are observationally
well constrained, apart from the largest entry, for warm plasma,
which still is driven by the need to balance the budget rather
than more directly by the observations. [...]

[Michael Mozina]

The universe that can be seen is smaller thna the universe that possibly exists?

The determination of the age of the universe is made rather accurately, the Hubble constant gets narrowed every year. But it is based upon the Hubble constant.

This is kind of interesting:
http://hubblesite.org/newscenter/archive/releases/2009/08/

Of course that particular measurement is based upon two primary assumptions:

A) Redshift is related *only* to expansion.
B) Everything (all matter and energy) was once condensed to a point.

The first assumption isn't all that difficult to defend, but the second assumption is virtually impossible to defend.

[QED]

Of course that particular measurement is based upon two primary assumptions:

A) Redshift is related *only* to expansion.
B) Everything (all matter and energy) was once condensed to a point.

The first assumption isn't all that difficult to defend, but the second assumption is virtually impossible to defend.
Let's disregard for a moment that no one claims redshift is *only* related to expansion (only that it is the dominant factor over large distances), B) isn't even an assumption at all, it is a consequence of A).

[DeiRenDopa]

Of course that particular measurement is based upon two primary assumptions:

A) Redshift is related *only* to expansion.
B) Everything (all matter and energy) was once condensed to a point.

The first assumption isn't all that difficult to defend, but the second assumption is virtually impossible to defend.Let's disregard for a moment that no one claims redshift is *only* related to expansion (only that it is the dominant factor over large distances), B) isn't even an assumption at all, it is a consequence of A).
Quite ...

... except that there are caveats; for example, no matter what density and/or temperature you are no longer comfortable with, when you 'run the clock backwards' on the observable universe, you won't get 'a point' ... there are those who run with some theory (perhaps too grand a word) which reconciles the deep inconsistencies between GR and QM in the Planck regime, but if you take a conservative view, you'll stop even well before then, at ~ten times the physics probed by the Tevatron perhaps.

You are quite right, of course, that estimates of the local (time) value of the Hubble constant* are quite independent of the details in cosmological models earlier than the time of BBN (say).

You could also have added, for MM's benefit, that the Hubble distance-redshift relationship has been studied intensively for many decades now, and is well supported by huge numbers of observations, of many different (independent) kinds. John Huchra's webpage on it (http://www.cfa.harvard.edu/~huchra/hubble/) is a good read.

* I'm guessing that's what MM is referring to

[Michael Mozina]

Let's disregard for a moment that no one claims redshift is *only* related to expansion (only that it is the dominant factor over large distances), B) isn't even an assumption at all, it is a consequence of A).

B) is most certainly an assumption. Alfven's "bang" did nothing of the sort. While you might be able to demonstrate *some* degree of concentration of matter and energy, you could never demonstrate it all came from a single point.

[Perpetual Student]

First, I invite you to join Skwinty ... download the paper (NOT the PR!), read it, and then ask questions (I'll be happy to try to help you understand the paper, and also show you how misleading the PR is).

Second, every conclusion drawn from astronomical observations comes with estimates of uncertainty. Further, in nearly every case, how the 'error budget' is determined is at least described (and in some cases, it is the sole topic of a string of very long papers!). Then, again in nearly every case, a clear distinction is made between estimated uncertainty due to known, essentially random factors, and estimated uncertainty due to systematic effects.

Systematic effects are the bane of astronomers' lives (or, to some, their primary research topic), and vast amounts of time and effort go into studying them. However, it is a fact of modern life that this 'back story' sells no papers, so you rarely see it (in PRs, popsci articles, etc, etc, etc). One unfortunate consequence is that all kinds of weird ideas start to float around the internet, based on little more than ignorance of estimates of uncertainty in astronomical results (and some folk apparently seek out this sort of thing to the exclusion of everything else).

Bottom line: if you are interested in the degree of confidence that can reasonably be given to any particular astronomical result, I think you have no choice but to roll up your sleeves and learn how the result was obtained, and what those engaged in doing the research have (and have not) already painstakingly taken account of.

OK, I'll climb down now.


Happy to oblige! :)

First, though, the sources.

This LAMBDA ("Legacy Archive for Microwave Background Data Analysis") webpage (http://lambda.gsfc.nasa.gov/product/map/current/map_bibliography.cfm) is by far the best single source ("Bibliography of WMAP Science Team Publications Five Year Data Scientific Papers"). The single paper you should read is "Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Likelihoods and Parameters from WMAP Data" (third from the bottom). If you haven't already done so, familiarise yourself with the cosmology tutorial on Ned Wright's website (http://www.astro.ucla.edu/~wright/cosmolog.htm); the FAQs include one called "Age of the Universe (http://www.astro.ucla.edu/~wright/age.html)"; I think that should answer your question.

The number you quoted earlier comes from a newspaper (!), but its likely source is a PR from the WMAP team, probably from their Three-Year results; you can learn about how observations of the CMB can be used to estimate the age of the universe from the LAMBDA webpage (above).

OK, thanks again; I will look at the information you provided. What amazes me about the presumed accuracy of the universe's age estimate is that, not only does it depend on the accuracy of observations, but that the age is not based on a simple extrapolation of a uniform rate. The rate has been accelerating for at least 9 billion years. So the actual beginning of the acceleration is not known exactly. But nevertheless: +/- .12 billion years (that's quite a feat)!

[Perpetual Student]

OK, thanks again; I will look at the information you provided. What amazes me about the presumed accuracy of the universe's age estimate is that, not only does it depend on the accuracy of observations, but that the age is not based on a simple extrapolation of a uniform rate. The rate has been accelerating for at least 9 billion years. So the actual beginning of the acceleration is not known exactly. But nevertheless: +/- .12 billion years (that's quite a feat)!

I have been following this for many years now. If I could, I would bet that the current consensus estimate will be different by at least a billion years ten years from now. Some new observations will surface, errors will be found, and/or new theories will develop.

[sol invictus]

Of course that particular measurement is based upon two primary assumptions:

A) Redshift is related *only* to expansion.
B) Everything (all matter and energy) was once condensed to a point.

The first assumption isn't all that difficult to defend, but the second assumption is virtually impossible to defend.

Good thing, then, that no results in cosmology depend on B), nor is B) a prediction or claim of the theory.

But we've discussed that more times than I can recall and it hasn't stopped you from posting exactly the same thing again and again, so I'm not going to bother.

[DeiRenDopa]

I have been following this for many years now. If I could, I would bet that the current consensus estimate will be different by at least a billion years ten years from now. Some new observations will surface, errors will be found, and/or new theories will develop.
The Wright FAQ page gives three independent methods of estimating the age of the universe, in addition to an estimate based on cosmological models (plus estimates of key parameters).

The 'error bars' on estimates based on each method (several estimates per method!) are far larger than +/- 0.12 billion years (Gyr), but the ranges all overlap.

The WMAP Five-Year paper I cited gives estimates of the densities of matter and dark energy; the Huchra website I cited gives a good summary of the history of estimates of the Hubble constant.

This LAMBDA/WMAP webpage (http://lambda.gsfc.nasa.gov/product/map/dr3/parameters_summary.cfm) is a table of the estimated values of the parameters, including the age of the universe. It is based on a WMAP Three-Year paper, and gives the age of the universe as 13.69 +/- 0.13 and 13.72 +/- 0.12 Gyr, with several critical footnotes, perhaps the most important of which is "The first value assumes the 6 parameter ΛCDM model using WMAP data only, the second using WMAP+BAO+SN data" (I've edited the footnote somewhat).

You'd need to read all relevant papers quite closely to determine just what the error bars are (typically, 68% confidence limits), and what key assumptions have been made in deriving those uncertainties.

Over the next few years perhaps the biggest single input to further constraining the age estimate (and estimated uncertainty) will be data from Planck ... and that data should also improve your comfort with the results (nothing better than independent validation, is there!). There's also a great deal of work going on on BAO (baryon acoustic oscillations) and SN (supernovae); results from that work will also, no doubt, further constrain the estimated age (and, perhaps, reduce the uncertainty).

A Gyr? Such a large change in the estimated age, derived from cosmological models, would seem unlikely; naively, that'd be ~8 sigma, which is as close to "impossible" as never mind. However, the error analysis that came up with +/- 0.12 Gyr is considerably more detailed and careful than what you find in a Statistics 101 textbook! Then there's the dependency on the actual model (who can say what will replace a six-parameter ΛCDM one?), as well as the values of the parameters in any such model.

[DeiRenDopa]

I think most readers will have some familiarity with the CMB (cosmic microwave background), WMAP (Wilkinson Microwave Anisotropy Probe), SN (or SNe, supernovae), but perhaps considerably less familiarity with BAO (Baryon Acoustic Oscillations).

If you've done a year or so of physics and/or math at university (YMMV), you may find this concise overview of BAO (http://astro.berkeley.edu/~mwhite/bao/) both interesting and helpful.

[Badly Shaved Monkey]

Incidentally I think the indicated position for the cold spot is about 180 degrees out in galactic latitude. The cold spot is on the bottom right - it's that blue/black region.

I am glad someone has said that. I thought I was just being stupid.

[DeiRenDopa]

The universe that can be seen is smaller thna the universe that possibly exists?

The determination of the age of the universe is made rather accurately, the Hubble constant gets narrowed every year. But it is based upon the Hubble constant.

This is kind of interesting:
http://hubblesite.org/newscenter/archive/releases/2009/08/
The "Related Links" part of that page has a link "Science Paper By: A. Riess et al. (PDF document)"; however, when I clicked on it I got gibberish.

Here (http://fr.arxiv.org/abs/0905.0695) is arXiv abstract version of that paper.

In a nutshell, Riess et al. embarked on a programme to reduce the estimated uncertainty in an estimate of H0 from ~11%, obtained in the Hubble Key Project (Freedman et al. 2001), to <5%. The paper reports the results, and success; the key to success may be summarised as reducing the uncertainties in the four largest sources of systematic error identified by Freedman et al.

[Michael Mozina]

Good thing, then, that no results in cosmology depend on B), nor is B) a prediction or claim of the theory.

But we've discussed that more times than I can recall and it hasn't stopped you from posting exactly the same thing again and again, so I'm not going to bother.

I fail to understand why you believe that I am somehow obligated to agree with you only because we've discussed the idea before. The fact of the matter is that none of us have any idea how compact the universe may have been at some point in the distant past.

[Perpetual Student]

A Gyr? Such a large change in the estimated age, derived from cosmological models, would seem unlikely; naively, that'd be ~8 sigma, which is as close to "impossible" as never mind.

I can only answer the above by saying the obvious:
We don't know what we don't know. That's why estimates of the age of the universe have been modified again and again over the years. Stay tuned!

[Zeuzzz]

I can only answer the above by saying the obvious:
We don't know what we don't know. That's why estimates of the age of the universe have been modified again and again over the years. Stay tuned!


Precisely. Period.

[sol invictus]

I fail to understand why you believe that I am somehow obligated to agree with you only because we've discussed the idea before.

Well, some people learn from having something explained to them. Pardon me for thinking that you might be one of them.

You made an assertion "Of course that particular measurement is based upon two primary assumptions:...
B) Everything (all matter and energy) was once condensed to a point" which is false (for multiple reasons, actually). Of course you've failed to back up that assertion (because it's false), and to make matters worse you ought to know it's false (because we've discussed it sickeningly many times already).

Does that sound like intellectually honest behavior, Michael?

I can only answer the above by saying the obvious:
We don't know what we don't know. That's why estimates of the age of the universe have been modified again and again over the years. Stay tuned!

That's not the issue. Sure, the age was revised many times as the data improved, as is the case with just about every quantity in the history of science. The question, though, is whether it was ever revised to something that fell significantly outside the error bars of the previous estimate, say by 4 sigma (let alone 8!).

I doubt it, but I don't know for sure - perhaps DRD can comment.

[Perpetual Student]

That's not the issue. Sure, the age was revised many times as the data improved, as is the case with just about every quantity in the history of science. The question, though, is whether it was ever revised to something that fell significantly outside the error bars of the previous estimate, say by 4 sigma (let alone 8!).

I doubt it, but I don't know for sure - perhaps DRD can comment.

It was not that many years ago that the number 20 billion years was thrown around.

[Perpetual Student]

It was not that many years ago that the number 20 billion years was thrown around.

Some years later it was 15 to 20 billion years.

[Michael Mozina]

Well, some people learn from having something explained to them. Pardon me for thinking that you might be one of them.

Pardon me for not agreeing with you "just because".

You made an assertion "Of course that particular measurement is based upon two primary assumptions:...
B) Everything (all matter and energy) was once condensed to a point" which is false (for multiple reasons, actually). Of course you've failed to back up that assertion (because it's false), and to make matters worse you ought to know it's false (because we've discussed it sickeningly many times already).

Um you seem to be under the illusion that A) you speak for everyone on this topic (your beliefs are all that matter) and B) I'm obligated to agree with you only because we've discussed it before. Neither assumption is true.

Does that sound like intellectually honest behavior, Michael?

What is not 'intellectually honest behavior" is your belief that your statements are "gospel" and no one is allowed to disagree with you once you have spoken with them about it.

That's not the issue. Sure, the age was revised many times as the data improved,

But somehow you've convinced yourself that won't happen again in the future?

[Michael Mozina]

http://en.wikipedia.org/wiki/Big_Bang

In 1931 Lemaître went further and suggested that the evident expansion in forward time required that the universe contracted backwards in time, and would continue to do so until it could contract no further, bringing all the mass of the universe into a single point, a "primeval atom", at a point in time before which time and space did not exist. As such, at this point, the fabric of time and space had not yet come into existence.[13]

Timeline of the Big Bang
See also: Timeline of the Big Bang
Extrapolation of the expansion of the universe backwards in time using general relativity yields an infinite density and temperature at a finite time in the past.[26] This singularity signals the breakdown of general relativity. How closely we can extrapolate towards the singularity is debated—certainly not earlier than the Planck epoch.

Whom shall I believe sol, you or Wiki?

[Michael Mozina]

http://en.wikipedia.org/wiki/Planck_epoch

Theoretical ideas

As there presently exists no widely accepted framework for how to combine quantum mechanics with relativistic gravity, science is not currently able to make predictions about events occurring over intervals shorter than the Planck time or distances shorter than one Planck length, the distance light travels in one Planck time—about 1.616 × 10-35 meters.

http://en.wikipedia.org/wiki/Planck_length

In physics, the Planck length, denoted \scriptstyle\ell_P \ , is a unit of length, equal to 1.616252(81)×10−35 meters. It is a base unit in the system of Planck units.

Sure sounds like a "point" from where I sit. Would the term "smaller than a breadbox" be more to your personal liking?

[Reality Check]

Some years later it was 15 to 20 billion years.
Some years later than that it was 16 to 19 billion years.
Some years later is was ~14 billion years.
Currently it is ~13.7 billion years.
I am not aware of what your point is. This is how all measurements in science are refined as new data is collected.

[sol invictus]

It was not that many years ago that the number 20 billion years was thrown around.
Some years later it was 15 to 20 billion years.

Question: do you know what an "error bar" is?


What is not 'intellectually honest behavior" is your belief that your statements are "gospel" and no one is allowed to disagree with you once you have spoken with them about it.

My statements about what the theory is and whether that assumption was necessary for that measurement were absolutely correct. Yours were wrong, as your own references below confirm. That's the same thing that happened last time - you were wrong, I was right, and all the references confirmed that. But you then went ahead and repeated the same intellectually dishonest statements.

http://en.wikipedia.org/wiki/Big_Bang


What Lemaître suggested in 1931 is now magically a "primary assumption" on which a contemporary measurement was "based"? On what planet do you spend most of your time, Michael?

Whom shall I believe sol, you or Wiki?Since wiki agrees with me and disagrees with you, it doesn't matter. "How closely we can extrapolate towards the singularity is debated—certainly not earlier than the Planck epoch. "
And yet you said "Everything (all matter and energy) was once condensed to a point." That's dead wrong, Michael.

http://en.wikipedia.org/wiki/Planck_epoch

http://en.wikipedia.org/wiki/Planck_length

Sure sounds like a "point" from where I sit.

A length sounds like a point to you, Michael? Really?

Would the term "smaller than a breadbox" be more to your personal liking?You tell me just what it is you think was smaller than a breadbox, and I'll answer that. If you respond "the volume of the universe", then your statement will be just as wrong.

[sol invictus]

But somehow you've convinced yourself that won't happen again in the future?

Did I say anything like that, Michael? Did I even imply it? No I didn't, did I? So why did you ask? Is that an intellectually honest tactic?

Question for you or PS: what does this http://www.ucolick.org/~bolte/papers/BolteHogan1995.pdf (http://www.ucolick.org/%7Ebolte/papers/BolteHogan1995.pdf) article tell you about the question I asked earlier ("The question, though, is whether it was ever revised to something that fell significantly outside the error bars of the previous estimate, say by 4 sigma (let alone 8!).")?

[DeiRenDopa]

I can only answer the above by saying the obvious:
We don't know what we don't know. That's why estimates of the age of the universe have been modified again and again over the years. Stay tuned!
At one extreme, we cannot know the age of the universe ... unless and until there is a totally satisfactory solution to the problem of induction (http://en.wikipedia.org/wiki/Problem_of_induction) (there is no guarrantee that the implicit or explicit solution employed in science, or part of it, will be satisfactory to you, even only once).

At the other extreme, the estimated age of the universe IS 13.69 +/- 0.13 and 13.72 +/- 0.12 Gyr (it's a particular estimate, arrived at using a method described in the paper in which it is published).

In my earlier post (http://forums.randi.org/showpost.php?p=5032944&postcount=380), I wrote about what the stated estimates of uncertainty mean, and how the age estimate itself is model-dependent (change the values of the parameters in the model, and the estimate will change; change the model itself, and you will have a different estimate).

Your post (which I'm quoting) seems to be about something in between; still science-based, but beyond even classes of models (and methods).

It's an interesting space! :) I'd like to explore it more, but I don't think this thread is the place to do so, and in any case, I doubt I'll have enough time and opportunity to do justice to it today (i.e. stay tuned!).

[DeiRenDopa]

It was not that many years ago that the number 20 billion years was thrown around.Some years later it was 15 to 20 billion years.
I wonder if someone has collected the various estimates and written them up, much like Huchra has done for the Hubble constant?

I recall, vaguely, that there were some interesting results a decade or three ago, concerning the estimated ages of various globular clusters (GCs); IIRC, the estimates were based on various models of stellar evolution, and CMDs (colour-magnitude diagrams), which summarise hundreds (or thousands) of individual observations. The GCs, or some of them, had estimated ages greater than the (then) estimated age of the universe1! :eek:

Might this be what you are referring to?

1 No prize for guessing how this apparent inconsistency is, or was, resolved ...

[Michael Mozina]

My statements about what the theory is and whether that assumption was necessary for that measurement were absolutely correct.

Oh for crying out loud. No "assumption" is "necessary" evidently, and none of you even agree on what is necessary. DRD doesn't even seem to think inflation theory is "necessary", but that is in fact the present "dogma". The notion that everything was collected together into one physically connected 'thing' (whatever you want to call it) is not something you could ever hope to demonstrate. It's an "act of blind faith". Period.

Yours were wrong, as your own references below confirm. That's the same thing that happened last time - you were wrong, I was right, and all the references confirmed that. But you then went ahead and repeated the same intellectually dishonest statements.

Baloney. You just went off on the word "point".

What Lemaître suggested in 1931 is now magically a "primary assumption" on which a contemporary measurement was "based"? On what planet do you spend most of your time, Michael?

It's still listed on Wiki as part of the 'dogma' sol. Why is that?

Since wiki agrees with me and disagrees with you, it doesn't matter. "How closely we can extrapolate towards the singularity is debated—certainly not earlier than the Planck epoch. "
And yet you said "Everything (all matter and energy) was once condensed to a point." That's dead wrong, Michael.

Does "singular mass body smaller than an atom" work for you?

A length sounds like a point to you, Michael? Really?

It really sounds to me like you're attempting to avoid the *POINT* of my statement and fixate on trivia.

You tell me just what it is you think was smaller than a breadbox, and I'll answer that. If you respond "the volume of the universe", then your statement will be just as wrong.

It seems to me that you aren't even going to deal with the point of my statements, you are intent on fixating on unimportant trivia (the term 'point') and you're engaging in hair splitting (atom size splitting as it were).

The point of my statement is that there is no way we can be sure how far back we can "wind the clock". There is no way to know that all mass and energy were collected together to anything smaller than say 5-10 percent of it's current size. There is no way to know that is was smaller than a breadbox, smaller than atom, or anywhere even *REMOTELY* close to a planks length. You go right ahead though and ignore the point entirely and smugly pat yourself on the back for fixating on trivia and avoiding the point of my post, but is that really "intellectually honest' of you sol?

[Michael Mozina]

Some years later than that it was 16 to 19 billion years.
Some years later is was ~14 billion years.
Currently it is ~13.7 billion years.
I am not aware of what your point is. This is how all measurements in science are refined as new data is collected.

So what makes you think new data won't radically alter than number again?

[sol invictus]

No "assumption" is "necessary" evidently, and none of you even agree on what is necessary.

So you admit you were wrong when you asserted "Of course that particular measurement is based upon two primary assumptions"?


Baloney. You just went off on the word "point".

Pardon me for taking your words seriously.


It's still listed on Wiki as part of the 'dogma' sol. Why is that?

Evidence? It's not in the part you quoted.


Does "singular mass body smaller than an atom" work for you?

Nope. What precisely is smaller? Do you mean, "the volume of the universe was smaller than the volume of an atom"? If so, that's just as wrong.


The point of my statement is that there is no way we can be sure how far back we can "wind the clock". There is no way to know that all mass and energy were collected together to anything smaller than say 5-10 percent of it's current size.

How did you arrive at the figure of 5-10%?


There is no way to know that is was smaller than a breadbox, smaller than atom, or anywhere even *REMOTELY* close to a planks length.

What was smaller?

[Michael Mozina]

So you admit you were wrong when you asserted "Of course that particular measurement is based upon two primary assumptions"?

No. I'll simply revise the word "point" to "lump".

Pardon me for taking your words seriously.

Pardon you for fixating on the word "point"' rather than the actual issue.

How did you arrive at the figure of 5-10%?

I pulled it out of my backside just like you pulled out any other number.

[sol invictus]

I'll simply revise the word "point" to "lump".

That's a yes. Good.

Question: in a few months, will you go back to using "point" even though you've agreed it was wrong?


I pulled it out of my backside

Thanks for admitting that. Are you interested in the real answer, the one that scientists have actually thought through and tested carefully?

[Michael Mozina]

That's a yes. Good.

Question: in a few months, will you go back to using "point" even though you've agreed it was wrong?

Oh no. I'll remember how intensely you tried to derail this conversation over a use of terms. "Lump" it is.

Are you interested in the real answer, the one that scientists have actually thought through and tested carefully?

You haven't "tested" anything in a controlled way. When you say "test", you aren't talking about anything with any sort of control mechanism or any sort of empirical test. It's all 'make-believe math' based on mythical dead inflation deities and "negative pressure vacuums".

[Perpetual Student]

Question: do you know what an "error bar" is?



I assume it means the same thing in physics as it does in other fields. Is it one standard deviation? As such, it would be based on the uncertainty of all the measurements made in calculating some value.
So, was the 15 to 20 billion years so often thrown around not so long ago based on one or two standard deviations? In any case, 13.7 billion years is certainly outside of that range.

[sol invictus]

Oh no. I'll remember how intensely you tried to derail this conversation over a use of terms. "Lump" it is.

It's annoying when people actually pay attention to the wrong things you say, isn't it Michael!


You haven't "tested" anything in a controlled way. When you say "test", you aren't talking about anything with any sort of control mechanism or any sort of empirical test. It's all 'make-believe math' based on mythical dead inflation deities and "negative pressure vacuums".I guess that's a "no". OK!

I assume it means the same thing in physics as it does in other fields. Is it one standard deviation?

Usually, yes (although it's a good idea to check in any particular plot).

As such, it would be based on the uncertainty of all the measurements made in calculating some value. Right.

So, was the 15 to 20 billion years so often thrown around not so long ago based on one or two standard deviations? In any case, 13.7 billion years is certainly outside of that range.

You'll have to provide a reference. Are you saying you think the result was 17.5 plus/minus 2.5 at one sigma? If it was, 13.7 is only off by about 1.5 sigma, which is perfectly normal and FAR below 4, let alone 8!

Remember, the probability is exponential in the number of standard deviations.

[Reality Check]

I assume it means the same thing in physics as it does in other fields. Is it one standard deviation? As such, it would be based on the uncertainty of all the measurements made in calculating some value.

In a statistical analysis you would be right, i.e. the error bars are selected as standard deviations (sigmas).
The 13.69 +/- 0.13 billion years has an uncertainties that is worked out from the uncertainties in the inputs to the parameters to the model used.
You need to read the papers cited by DeiRenDopa to get the exact method used to determine the uncertainties.


So, was the 15 to 20 billion years so often thrown around not so long ago based on one or two standard deviations? In any case, 13.7 billion years is certainly outside of that range.
I do not know where you get this 15 to 20 billion years or what "not so long ago" means.
The Age of the Universe (http://www.astro.ucla.edu/~wright/age.html)web page by Ned Wright has measurements from ~1999 as:
11.5-17.5 Gyr and 12.3-17.3 Gyr from radioactive decay.
15.2 +/- 3.5 Gyr, 15.6 +/- 4.6 Gyr, 12.5 +/- 3 and 14.1 +/- 2.5 from ages of stars.
etc.

Can you give a citation?

[DeiRenDopa]

Question: do you know what an "error bar" is? I assume it means the same thing in physics as it does in other fields.
One of the things I tried to explain - unsuccessfully it seems - is that one cannot rely upon the assumption that an error bar (or uncertainty) in the abstract of a paper is estimated by any particular method ... you actually need to read the paper to learn what the estimated uncertainty is and how it was calculated.

Is it one standard deviation? As such, it would be based on the uncertainty of all the measurements made in calculating some value.
In the case of WMAP team papers, a very great deal of work has gone into estimating the uncertainties, and I think you'll find the +/- values are 68% confidence limits. While this seems to the same as one sigma, I think you'll find there are some differences. Further, at least some papers also quote 95% and 99% CLs (IIRC, I could be wrong), and if you do some simple arithmetic on them, you'll see they cannot be 2 and 3 sigma (respectively).

Normally I'd offer to go through a paper or two on this, to help you (and any other reader) understand what has actually been done, but in this case I am not prepared to do so ... the effort would be far greater than the time I have available (the analyses are very extensive, and are presented in a number of quite heavy papers); perhaps another JREF Forum member might like to step in?

So, was the 15 to 20 billion years so often thrown around not so long ago based on one or two standard deviations? In any case, 13.7 billion years is certainly outside of that range.
I see this point has already been addressed ...

[Perpetual Student]

This age of the universe discussion has gone beyond my purpose in bringing it up in the first place. Please understand that I have a very deep respect for all the physicists, astronomers and cosmologists who work in this field. I understand that these estimates are based on a lot of hard work and meticulous analysis and calculations. I do not want to be cast in the role of one who in any way depreciates the value of their work and achievements.
I am basing my comments on my more than 50 years of following developments in this area. I have witnessed drastic revisions in cosmological theories several times (in my youth Fred Hoyle seemed to have all the answers -- think about that -- continuous creation of one hydrogen atom per cubic meter per year -- or something like that). I simply feel that it is naive to believe that "now we've got it right." Based on my experience in this area I have come to expect the unexpected. Nevertheless, DieR. you have been very helpful in providing material that gives me some reason to believe that the current estimate is far more well founded than those of the past and finally, we may be on the trail of the ultimate answer -- maybe. Thanks again, I will continue to read and attempt to comprehend the sources you have recommended.

[Perpetual Student]

Are you saying you think the result was 17.5 plus/minus 2.5 at one sigma?

I have no idea. 15 to 20 billion years was a range often repeated in cosmological discussions.
If it was, 13.7 is only off by about 1.5 sigma, which is perfectly normal and FAR below 4, let alone 8!

Remember, the probability is exponential in the number of standard deviations.
OK, good points.