Will all matter/energy eventually evolve in to a state of inert uniformity?

[ynot]

Or will forms of life always collect and reform matter/energy in to distinct entities? Or perhaps something entirely different?

[Dilb]

If I understand any cosmology (I might not);

If the universe continues to expand (more than gravity causes it to collapse), eventually everything will cool down and reach maximum entropy. Life is just a mechanism to redirect entropy (more or less, in my opinion), so it won't have any impact on physics. Matter will continue to be distict, as much as it is distinct right now.

Alternatively, the universe will collapse down to a singularity (gravity wins, compared to expansion), where all bets are off.

[Dave1001]

If I understand any cosmology (I might not);

If the universe continues to expand (more than gravity causes it to collapse), eventually everything will cool down and reach maximum entropy. Life is just a mechanism to redirect entropy (more or less, in my opinion), so it won't have any impact on physics. Matter will continue to be distict, as much as it is distinct right now.

Alternatively, the universe will collapse down to a singularity (gravity wins, compared to expansion), where all bets are off.

Well, at the end point of entropy, it's hard for me to imagine life existing, because the entire universe would be uniformly homogenous. Life (and more to the point for me, subjective consciousness) seems to me to require non-uniformity at the very least.

A question I have, is if the endpoint of an expanding, entropic universe is an actual fixed date, or is it asymptotic? If it's asymptotic, I think life (and subjective consciousness) would be able to persist simply by increasing its efficiency at a rate equal to entropy.

Perhaps the same with a collapsing universe, where I think reverse entropy would occur. If the singularity is asymptotic, then once again perhaps life (and subjective consciousness) would only have to adapt at a rate equal to the rate of collapse to persist.

[Yllanes]

Perhaps the same with a collapsing universe, where I think reverse entropy would occur. If the singularity is asymptotic, then once again perhaps life (and subjective consciousness) would only have to adapt at a rate equal to the rate of collapse to persist.

A collapsing universe would take a finite time to collapse. In the simple Friedmann cosmology, the size of the universe with respect to a time parameter follows a cycloid. Same time to collapse than it took it to expand to its maximum size. And the idea of reverse entropy, popularised by the Brief History of Time has now been abandoned (http://www.astro.ucla.edu/~wright/cosmology_faq.html#EBC).

This is a nice, simple, source (http://math.ucr.edu/home/baez/end.html) on what it will happen to our universe at really wild time scales. I really recommend it. In relation to your asymptotic idea:


Freeman Dyson has discussed the fate of intelligent life in the far future assuming a perpetually expanding universe, but assuming the cosmological constant is zero. In this situation the temperature of the universe decreases ever closer to absolute zero, and Dyson figured out that in principle, intelligent life could last forever and think an infinite number of thoughts, although slower and slower. This idea seems to be ruined by the presence of a nonzero cosmological constant and the resulting nonzero lower bound on the temperature.

[ynot]

Well, at the end point of entropy, it's hard for me to imagine life existing, because the entire universe would be uniformly homogenous. Life (and more to the point for me, subjective consciousness) seems to me to require non-uniformity at the very least.

A question I have, is if the endpoint of an expanding, entropic universe is an actual fixed date, or is it asymptotic? If it's asymptotic, I think life (and subjective consciousness) would be able to persist simply by increasing its efficiency at a rate equal to entropy.

Perhaps the same with a collapsing universe, where I think reverse entropy would occur. If the singularity is asymptotic, then once again perhaps life (and subjective consciousness) would only have to adapt at a rate equal to the rate of collapse to persist.
There could be life, but not as we know it Jim. Perhaps life could evolve to survive in whatever conditions exist as the rest of the universe evolves towards a state of entropy. It seems to me that life tends to buck the trend toward entropy by continuously reforming energy and matter to recreate itself anew. Does this mean that, if life can continue to survive in some form, it may prevent a state of complete entropy every happening? Ignoring of course the possibility and side effects of the theorised Big Shrink.

[Iamme]

I think the question posed has to cause us to think and re-think the position taken on how the state of our universe came into being, as we now see it. The fact is, we have great heat and light separated by great cold and darkness. I find this fascinating. One can easily suppose that initially the universe was plasma soup. But with such thinking, one has to wonder what, during what point in time, did it decide to separate, as is also stated in the Bible. Why would it separate? That is the million dollar question. If you believe that it ever DID separate, you must carefully firgure what would have triggered it to do so after milliseconds, or after millennia, to separate.

Creation them came from WHAT form, exactly?

And to understand by what way it wil return acgain to what it was, or if it won't, we HAVE to understand in what form or from what the universe came.

[ynot]

I think the question posed has to cause us to think and re-think the position taken on how the state of our universe came into being, as we now see it. The fact is, we have great heat and light separated by great cold and darkness. I find this fascinating. One can easily suppose that initially the universe was plasma soup. But with such thinking, one has to wonder what, during what point in time, did it decide to separate, as is also stated in the Bible. Why would it separate? That is the million dollar question. If you believe that it ever DID separate, you must carefully firgure what would have triggered it to do so after milliseconds, or after millennia, to separate.

Creation them came from WHAT form, exactly?

And to understand by what way it wil return acgain to what it was, or if it won't, we HAVE to understand in what form or from what the universe came.
Does the question posed cause us think and rethink the position we take on how the state of our universe came into being. Or does it cause us think and rethink on how it might fit in with and support the existing position we take?

[fuelair]

I think the question posed has to cause us to think and re-think the position taken on how the state of our universe came into being, as we now see it. The fact is, we have great heat and light separated by great cold and darkness. I find this fascinating. One can easily suppose that initially the universe was plasma soup. But with such thinking, one has to wonder what, during what point in time, did it decide to separate, as is also stated in the Bible. Why would it separate? That is the million dollar question. If you believe that it ever DID separate, you must carefully firgure what would have triggered it to do so after milliseconds, or after millennia, to separate.

Creation them came from WHAT form, exactly?

And to understand by what way it wil return acgain to what it was, or if it won't, we HAVE to understand in what form or from what the universe came.

In the most general form (this is the subject of books so.....): In the initial big bang the material exploded out was close to, but not perfectly, spread out and the very small differences slowly but surely caused some of the material to coalesce (i.e. gravity effects occured where distribution was not perfectly even) over a really long time into galaxies, stars (and failed stars) planets around the stars, moons around some planets (but not the only way they could occur), etc. The Bible does not really cover this - and is not a book I would be using for that purpose.

[SezMe]

As I understand it, there is some evidence now that the expansion is accelerating, not decelerating. Are we going into another inflationary period?

If there is a next inflationary period and it happens as fast as the first one, the whole universe will cease to exist as we know it in milliseconds.

That'll hurt.

[ynot]

As I understand it, there is some evidence now that the expansion is accelerating, not decelerating. Are we going into another inflationary period?

If there is a next inflationary period and it happens as fast as the first one, the whole universe will cease to exist as we know it in milliseconds.

That'll hurt.
Not confusing the universe with the monetary system are you? If you are that’ll still hurt. :D

[epepke]

There could be life, but not as we know it Jim. Perhaps life could evolve to survive in whatever conditions exist as the rest of the universe evolves towards a state of entropy. It seems to me that life tends to buck the trend toward entropy by continuously reforming energy and matter to recreate itself anew.

Perhaps it seems that way to you, but it really doesn't. Life accelerates the increase of entropy. Life (and evolution) seem to work a bit like heat engines in this regard. It extracts useful local decreases in entropy at the expense of a much greater global increase.

[TV's Frank]

As I understand it, there is some evidence now that the expansion is accelerating, not decelerating. Are we going into another inflationary period?

If there is a next inflationary period and it happens as fast as the first one, the whole universe will cease to exist as we know it in milliseconds.

That'll hurt.

Yes, we are currently in another inflationary phase (it actually started about 5 billion years ago), but it is much much weaker than the earlier inflationairy phase, and we're not sure if the two are related.

[SezMe]

Not confusing the universe with the monetary system are you? If you are that’ll still hurt. :D

I think you need to do some reading about the big bang and then come back here and discuss who has what pain. The inflationary period in big bang cosmology plays a central role in our understanding of the physics of the universe we live in.

[SezMe]

Yes, we are currently in another inflationary phase (it actually started about 5 billion years ago), but it is much much weaker than the earlier inflationairy phase, and we're not sure if the two are related.
You appear to be well ahead of me. I thought the existence of the current inflationary phase was still subject to debate much less knowing how it might relate to the earlier one. I'd be interested in some links to current research if you have them.

[ynot]

I think you need to do some reading about the big bang and then come back here and discuss who has what pain. The inflationary period in big bang cosmology plays a central role in our understanding of the physics of the universe we live in.
Touchy, touchy. In case you missed it, my comment was merely an attempt at humour (hence the big grin smiley). Perhaps one of us is not very good at humour.

[Dave1001]

There could be life, but not as we know it Jim. Perhaps life could evolve to survive in whatever conditions exist as the rest of the universe evolves towards a state of entropy. It seems to me that life tends to buck the trend toward entropy by continuously reforming energy and matter to recreate itself anew.


I haven't been accused of lacking imagination, but I have trouble seeing how life could exist at an entropic endpoint. Wouldn't the universe be completely homogenous, and at a temperature of absolute zero? I think this is a different problem than how life deals with entropy at the present, in a universe still relatively rich with matter-energy non-homogeneity.


Does this mean that, if life can continue to survive in some form, it may prevent a state of complete entropy every happening? Ignoring of course the possibility and side effects of the theorised Big Shrink.


I do hold out hope that intelligent life may be able to reengineer the universe so as to thwart reaching an entropic endpoint (or a Big Shrink endpoint). I suspect the technology to do that, if it is even possible, is so far in the future that current speculation on it would be silly (but maybe fun).

[TV's Frank]

You appear to be well ahead of me. I thought the existence of the current inflationary phase was still subject to debate much less knowing how it might relate to the earlier one. I'd be interested in some links to current research if you have them.

A good review paper is the one by Sean, Carroll, and Trodden:
http://arxiv.org/abs/astro-ph/0510059

Measurements from the CMB, distant supernovae, and galaxy clusters all point to a universe that is around 75% "dark energy". If could be that a scalar field with certain characteristics could be responsible for this "dark energy", and hence accelerated expansion, which would be the same as the source for inflation.

If this is the case, then yes, you can make the same field responsible for both periods of inflation, by playing with the equations. But, the timescales and energies involved are so wildly different that it's easier to consider it as two separate fields. You don't gain anything but headaches by combining them. The moral: even if they were the same field, it's just easier to consider them as two separate ones anyway.

[fuelair]

I haven't been accused of lacking imagination, but I have trouble seeing how life could exist at an entropic endpoint. Wouldn't the universe be completely homogenous, and at a temperature of absolute zero? I think this is a different problem than how life deals with entropy at the present, in a universe still relatively rich with matter-energy non-homogeneity.



I do hold out hope that intelligent life may be able to reengineer the universe so as to thwart reaching an entropic endpoint (or a Big Shrink endpoint). I suspect the technology to do that, if it is even possible, is so far in the future that current speculation on it would be silly (but maybe fun).

Not at absolute zero, just barely above absolute zero.

[Dave1001]

Not at absolute zero, just barely above absolute zero.

ok, why wouldn't an entropic endpoint (even if that endpoint is itself asymptotic) be absolute zero? That would seem to me to be definitional. What am I missing here?

[Yllanes]

ok, why wouldn't an entropic endpoint (even if that endpoint is itself asymptotic) be absolute zero? That would seem to me to be definitional. What am I missing here?

The cosmological constant. It is all explained in the link I gave above (http://math.ucr.edu/home/baez/end.html):


So the question is, which effect wins as the universe expands: the decreasing density (which makes matter want to ionize) or the decreasing temperature (which makes it want to stick together)?

In the short run this is a fairly complicated question, but in the long run, things may simplify: if the universe is expanding exponentially thanks to a nonzero cosmological constant, the density of matter obviously goes to zero. But the temperature does not go to zero. It approaches a particular nonzero value! So all forms of matter made from protons, neutrons and electrons will eventually ionize!

Why does the temperature approach a particular nonzero value, and what is this value? Well, in a universe whose expansion keeps accelerating, each pair of freely falling observers will eventually no longer be able to see each other, because they get redshifted out of sight. This effect is very much like the horizon of a black hole - it's called a "cosmological horizon". And, like the horizon of a black hole, a cosmological horizon emits thermal radiation at a specific temperature. This radiation is called Hawking radiation. Its temperature depends on the value of the cosmological constant. If we make a rough guess at the cosmological constant, the temperature we get is about 10-30 Kelvin.

This is very cold, but given a low enough density of matter, this temperature is enough to eventually ionize all forms of matter made of protons, neutrons and electrons! Even something big like a neutron star should slowly, slowly dissipate. (The crust of a neutron star is not made of neutronium: it's mainly made of iron.)

[Cuddles]

ok, why wouldn't an entropic endpoint (even if that endpoint is itself asymptotic) be absolute zero? That would seem to me to be definitional. What am I missing here?

Any particle or system has a ground state that is the lowest energy it can possibly have. Since the ground state is not equal to zero, particles cannot lose all their energy and so will never quite reach absolute zero.

I read a very good explanation of how life could prolong it's existence in a universe expanding for ever. Using a definition of life to be the act of perfoming calculations (since this is the most basic requirement for life), as energy becomes more spread out the rate of calculation will slow down, but will never actually reach zero. The end point would be when the rate of calculation is so slow that an entity would effectively be in suspended animation, with the final calculation being performed at an infinte time in the future. Unfortunately I have no idea where I read this. I think it was in a book.

[Yllanes]

I read a very good explanation of how life could prolong it's existence in a universe expanding for ever. Using a definition of life to be the act of perfoming calculations (since this is the most basic requirement for life), as energy becomes more spread out the rate of calculation will slow down, but will never actually reach zero. The end point would be when the rate of calculation is so slow that an entity would effectively be in suspended animation, with the final calculation being performed at an infinte time in the future. Unfortunately I have no idea where I read this. I think it was in a book.

As I said before, this is an idea by Freeman Dyson, but it breaks with the existence of a cosmological constant.

Some papers discussing this:

http://arxiv.org/abs/astro-ph/9902189

http://www.arxiv.org/abs/astro-ph/0205279

From the first one


Current evidence suggests that the cosmological constant is not zero, or that we live in an open universe. [...] If the Universe is cosmological constant-dominated, our ability to probe the evolution of large scale structure will decrease with time — presently observable distant sources will disappear on a time-scale comparable to the period of stellar burning. Moreover, while the Universe might expand forever, the integrated conscious lifetime of any civilization will be finite, although it can be astronomically long. [...] In the absence of possible exotic and uncertain strong gravitational effects [...] life cannot be eternal.



The picture we have painted here is not optimistic. [...]The universe will become noticeably less observable on a time-scale which is fathomable. Moreover, in such a universe, the days — either literal or metaphorical — are numbered for every civilization. More generally, perhaps surprisingly, we find that eternal sentient material life is implausible in any universe. The eternal expansion which Dyson found so appealing is a chimera.

We can take solace from two facts. [...] The actual time frames of interest [...] are extremely long, in excess of 1050−10100 years, depending upon cosmological and biological issues. On such time-scales much more pressing issues, including the death of stars, and the possible ultimate instability of matter, may determine the evolution of life.

Next, and perhaps more important, strong gravitational effects on the geometry or topology of the universe might effectively allow life, or information, to propagate across apparent causal boundaries, or otherwise obviate the global spatial constraints we claim here. [...] While these are interesting possibilities, at this point they are vastly more speculative than the other possibilities we have discussed here.

[Darth Rotor]

Or perhaps something entirely different?

The discussion your question raised seems to have an unwritten, unvoiced assumption that the expansion is omnidirectional akin to the spherical spreading of heat radiation in still water, or in a near vacuum.

I am no ace at cosmology, but it seems that the universe's space-time is bounded. Bodies move, at the star and star system level, in exotic ways, in curves, and non linearly near gravity wells and black holes. With the anaolgy of a physical model of a system that doesn't perfectly model the system, I am uncomfortable with the line of thinking that assumes expansion as an omnidirectional flight from "point Bang."

If the expansion "curves" or moves in non linear fashion over time (as in millenia and eons) then our observations at the moment are a very delicate application of a "French Curve" over some narrowly measured data points. I suspect ironing out such puzzles in one of many topics of research at present.

(OK, who here is old enough to have used French curves to graph out test results????)

Interesting discussion, in any event, and a fine companion to my first cup of coffee this morning. Thanks to all. :cool:

DR

[Dr Adequate]

ok, why wouldn't an entropic endpoint (even if that endpoint is itself asymptotic) be absolute zero? That would seem to me to be definitional. What am I missing here? Entropy is created when heat flows. Heat flows from bodies of one temperature to bodies of another temperature. When everything's the same temperature, no more heat can flow, ergo no more entropy can be created. So when everything's the same temperature, that's as much entropy as you can get.

[Dave1001]

Any particle or system has a ground state that is the lowest energy it can possibly have. Since the ground state is not equal to zero, particles cannot lose all their energy and so will never quite reach absolute zero.

I read a very good explanation of how life could prolong it's existence in a universe expanding for ever. Using a definition of life to be the act of perfoming calculations (since this is the most basic requirement for life), as energy becomes more spread out the rate of calculation will slow down, but will never actually reach zero. The end point would be when the rate of calculation is so slow that an entity would effectively be in suspended animation, with the final calculation being performed at an infinte time in the future. Unfortunately I have no idea where I read this. I think it was in a book.

Hmm, that's not of an opiate for this member of the masses. It's not calculations that I want to persist, it's my real time subjective conscious state. Perhaps subjective consciousness can also be reduced to the act of performing calculations. But I suspect that a minimum threshold of amount of calculations is necessary for a subjective conscious state as a human experiences it to persist. Also, I'm skeptical that a single final calculation in suspended animation will be anything like an enjoyable subjective conscious experience. Also, is that final infitinitely long calculation itsel asymptotic? After all, a fraction of an infinitely long calculation is also infinite. So wouldn't the next to last calculation, etc. also be infinite? So that would seem to indicate an asymptotic endpoint to entropy in an infinitely expanding universe, rather than a fixed endpoint. Am I missing anything here in my understanding of your post?

[Iamme]

Regarding what we need to rethink: I think we need to rethink what made and started the universe so that it could even BE in this inflationary phase.

It boggles the mind that you would have this marble out there that was just there?...and exploded, as to create this enormity...that we have to ponder if it will ever come back together...to make a marble again?...so that it can do it yet again?...and again?..and again?

Doesn't this sound rather peculiar? Doesn't this seem like there has to be another explanation to this whole thing?

And do you know what else is odd? Of all the stuff I have read and seen regarding the universe, nobody talks about what that HUGE bright light is in the middle of each galaxy? It's not a black hole...because black holes are...black. And I never them call it a gigantic star. It's just huge...and it's bright. What is it?

[Dave1001]

Regarding what we need to rethink: I think we need to rethink what made and started the universe so that it could even BE in this inflationary phase.

It boggles the mind that you would have this marble out there that was just there?...and exploded, as to create this enormity...that we have to ponder if it will ever come back together...to make a marble again?...so that it can do it yet again?...and again?..and again?

Doesn't this sound rather peculiar? Doesn't this seem like there has to be another explanation to this whole thing?


I don't know if there's a better explanation or not, but whatever the better explanation is, it will probably sound peculiar to us too. Our brains evolved to know where different fruits and nuts were in a savannah, not to understand the cosmos. So we should expect scales of the universe that we didn't evolve to comprehend to appear non-intuitive to us.


And do you know what else is odd? Of all the stuff I have read and seen regarding the universe, nobody talks about what that HUGE bright light is in the middle of each galaxy? It's not a black hole...because black holes are...black. And I never them call it a gigantic star. It's just huge...and it's bright. What is it?

Well, I'm not sure black holes can't be surrounded by bright light, if there is a greater density of stars there. We're probably seeing the stars clustered around the black hole, not the black hole itself.

[DrCron]

Well sooner or later protons will decay, at which point the whole argument is moot. They don't quite have the data or the math to say when, but some time in the far far future all that will be left is photons.

[Dave1001]

Well sooner or later protons will decay, at which point the whole argument is moot. They don't quite have the data or the math to say when, but some time in the far far future all that will be left is photons.

I don't see why the argument is moot at that point. In terms of my particular concern, sure the substrate for subjective conscious existence would have to change at that point, but since matter-energy would still be non-homogeneous, I don't see why in principle life & consciousness couldn't still exist.

[Cuddles]

Hmm, that's not of an opiate for this member of the masses. It's not calculations that I want to persist, it's my real time subjective conscious state. Perhaps subjective consciousness can also be reduced to the act of performing calculations. But I suspect that a minimum threshold of amount of calculations is necessary for a subjective conscious state as a human experiences it to persist. Also, I'm skeptical that a single final calculation in suspended animation will be anything like an enjoyable subjective conscious experience. Also, is that final infitinitely long calculation itsel asymptotic? After all, a fraction of an infinitely long calculation is also infinite. So wouldn't the next to last calculation, etc. also be infinite?

The idea of calculations is to give a quantifiable thing that equates to your subjective conciousness. It is not relevant to the theory how many calculations are required for conciousness, the answer will still come out the same. I think the idea was that although calculation would slow down, and eventually stop, this would happen an infinite time in the future. Effectively you would never notice the slowdown, since it your awareness that is slowing down. Since the rate of calculation approaches zero assymptotically, you will perform a finite number of calculations in an infinite time, so although you will technically live for ever it won't seem like this from your personal point of view.

So that would seem to indicate an asymptotic endpoint to entropy in an infinitely expanding universe, rather than a fixed endpoint.

Yes. Entropy will continue increasing, but at a decreasing rate, so although there will be a final maximum value, this would only be reached after an infinite time.

All these arguments are made without considering any quantum mechanics (as far as I'm aware), so ground states and zero-point energy will make major changes to the outcome. I would think that the existence of ground states will mean entropy stops increasing when all particles reach their ground state and no calculations would be possible after this point. Vaccuum fluctuations would mean this final state would not be completely static, but energy variations would be random noise and not of any practical use.

Am I missing anything here in my understanding of your post?

I'm probably missing things in my understanding of my own posts, so I wouldn't be at all surprised if what I'm saying isn't the same as what I mean to say.

[hammegk]

Is the thread title suggesting the universe will eventually reach the same state now exhibited by some internet-forum moderator/administrator coteries?

[Dave1001]

Is the thread title suggesting the universe will eventually reach the same state now exhibited by some internet-forum moderator/administrator coteries?

:D :D :D

[Dave1001]

Since the rate of calculation approaches zero assymptotically, you will perform a finite number of calculations in an infinite time, so although you will technically live for ever it won't seem like this from your personal point of view.

.

Why wouldn't it seem like it from my personal point of view. It seems to me like living forever is just a state of subjective conscious awareness that never stops persisting. If the final calculations asympotical approach infinite lengths, and my subjective conscious awareness persists within those final calculations, when exactly would I cease existing?

Complicating all this might be (1) if subjective conscious awareness has a maximum speed limit of calculations in which to persist, such as the speed at which our neurons fire or some such thing, and (2) if infinities don't really exist in the real universe. I recall reading about a theory that space-time-matter-energy actuall does have smallest discreet units, and there is a finite number of them in the universe. If that's true, then I imagine things won't happen asymptotically, and that we're on a real, fixed clock to an entropic endstate.

Anyone with a better knowledge of physics and current theories want to weigh in on this?

[Genesius]

Is the thread title suggesting the universe will eventually reach the same state now exhibited by some internet-forum moderator/administrator coteries?
:D :D :D

For Ed's sake, don't encourage him!

[DrCron]

I don't see why the argument is moot at that point. In terms of my particular concern, sure the substrate for subjective conscious existence would have to change at that point, but since matter-energy would still be non-homogeneous, I don't see why in principle life & consciousness couldn't still exist.

Actually, at that point matter-energy would be homogeneous. Except for quantum fluxuation I think. In short, no life, at least until we have a total revamping of physics to allow for control of what are now seen as truly random events.