Is the Heat Death of the Universe Inevitable and What Can We Do About It?

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Discussion Overview

The discussion revolves around the concept of the heat death of the universe, exploring its inevitability and potential alternatives such as the Big Crunch or Big Rip scenarios. Participants examine theoretical implications, the role of dark energy, and speculative ideas about the universe's fate.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification
  • Speculative reasoning

Main Points Raised

  • Some participants assert that the heat death of the universe is a widely supported theory, while others suggest that dark energy's role is not fully understood, leaving room for alternative scenarios like the Big Crunch.
  • A hypothesis is proposed that a society could potentially extend its existence through advanced technology, such as habitats utilizing black hole Hawking radiation, but ultimately entropy would prevail.
  • There are conflicting views on whether dark energy could weaken over time, allowing gravity to dominate and potentially lead to a Big Crunch, with some arguing that current models do not support this.
  • Some participants mention the Big Rip as a possible outcome, contingent on the behavior of dark energy, which remains a topic of debate.
  • Clarifications are made regarding the relationship between dark energy and gravitational forces, with some participants expressing uncertainty about the implications of their statements.
  • Speculative ideas are introduced, such as the "Big Bounce" scenario, where the universe oscillates between hot and cold states, suggesting a cyclical nature of cosmic evolution.

Areas of Agreement / Disagreement

Participants express a mix of agreement and disagreement regarding the inevitability of heat death, the role of dark energy, and the plausibility of alternative scenarios like the Big Crunch or Big Bounce. The discussion remains unresolved with multiple competing views present.

Contextual Notes

Limitations include the speculative nature of many claims, dependence on current models of dark energy and gravity, and unresolved questions about the universe's geometry and its implications for future scenarios.

Delong
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I heard that eventually the universe will end in heat death where everything becomes cold and lifeless and immotile. Is this true and is it inescapable? What can we perhaps do about it?
 
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That is the current theory and it is widely supported by most scientists and by the evidence. There IS a theory (maybe more than one?) that suggests that dark energy is not yet well enough understood (hey, there's an understatement for you!) to rule out the possibility that the currently accelerating expansion will eventually reverse and there will be a big crunch, but I don't know how seriously, if at all, such theories are taken by mainstream science.
 
Presuming the universe progresses as we currently think it should (i.e. no big crunch, no false vacuum though neither of those seem particularly survivable) it doesn't look like there's anything we can do to avoid the heat death. Hypothetically a society may survive longer by constructing habitats with ultra-efficient recycling that take their energy from black hole Hawking radiation but inevitably entropy will win.
 
Delong said:
I heard that eventually the universe will end in heat death where everything becomes cold and lifeless and immotile. Is this true and is it inescapable? What can we perhaps do about it?

If DE (Dark Energy) is not sufficiently strong enough to overcome gravity at some point in the future, then eventually all last vestiges of matter/energy will be spread over incredibly vast differences and essentially will be so diffuse as to enter "heat death". This "heat death" would then be a perpetual state as matter/energy interactions occur in very small and almost unnoticeable ways.

However this is only assuming current models. As phinds has pointed out in his previous post there are theories that refute our current understanding of DE and its continued role on a large scale level on the Universes evolution. If our current understanding are wrong and density of the Universe exceeds critical density then essentially this will result in a "Big Crunch" - however as stated this is speculative and against current comsmo model consensus.

Asking what we can "perhaps do about it" is not really a valid question. On a planetary level we have little influence - so to extend this to solar, galactic and universal levels accomplishes nothing. To be able to do anything about it we would need to be able to fundamentally alter laws of physics in currently incomprehensible ways! Essentially we would need a "magic technology X" which is neither plausible not probable and some would argue is impossible.

I must admit I love the optimism though! :smile:
 
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Don't forget about the Big Rip! While this would require a form of phantom energy with p < -\rho which is quantum mechanically unstable and leads to a host of other pathologies, current data does seem to favor it.
 
Cosmo Novice said:
If DE (Dark Energy) is not sufficiently strong to overcome the acceleration forces of expansion,

You've contradicted yourself with the statement above. DE is not something that is going to overcome the acceleration, DE CAUSES the acceleration. The only hope of the "big crunch" theories is that DE isn't strong enough to CONTINUE the accelerated expansion AND something else happens to reverse the expansion (I THINK, but am not sure, that I have read that at this point, even if DE went away, gravity would not longer be able to reverse the expansion, so the "big crunch" is going to require a fundamental change in SOMETHING.
 
phinds said:
(I THINK, but am not sure, that I have read that at this point, even if DE went away, gravity would not longer be able to reverse the expansion, so the "big crunch" is going to require a fundamental change in SOMETHING.
I'm pretty sure that depends on the global geometry of the universe. If the universe is closed, and all the dark energy simply went away, then we would be left with a closed matter dominated universe and a big crunch would be inevitable.
 
phinds said:
You've contradicted yourself with the statement above. DE is not something that is going to overcome the acceleration, DE CAUSES the acceleration.

Thankyou, I wrote this at work very quickly and when I re-read it back just now it makes absolutlety no sense! I have edited accordingly and thankyou for pointing that out.
 
  • #10
bapowell said:
I'm pretty sure that depends on the global geometry of the universe. If the universe is closed, and all the dark energy simply went away, then we would be left with a closed matter dominated universe and a big crunch would be inevitable.

Could be I have a fundamental misunderstanding, but if I have it right, your logic is circular. Because spacetime is affected by gravity, it IS gravity that determines whether or not the U is open or closed (or flat) and if that's the case then your argument is circular. I'm new to all this and as I said, I recognize that I may have that wrong.
 
  • #11
phinds said:
Could be I have a fundamental misunderstanding, but if I have it right, your logic is circular. Because spacetime is affected by gravity, it IS gravity that determines whether or not the U is open or closed (or flat) and if that's the case then your argument is circular. I'm new to all this and as I said, I recognize that I may have that wrong.
He just pointed out a physical scenario under which we might get a big crunch without any sort of fundamental change in gravity. It does require that the dark energy changes its behavior dramatically in the future, but other than that no change is necessary.

That said, the expectation right now is a universe which expands forever, and in that situation a heat death is inevitable.
 
  • #12
Delong said:
I heard that eventually the universe will end in heat death where everything becomes cold and lifeless and immotile. Is this true and is it inescapable? What can we perhaps do about it?

No one knows for sure yet; so all of this is in the speculative nature.

So here is some speculation!

Let’s consider “Heat Death” as regards to a "Big Bounce" scenario for an "Oscillating" model of the Universe. Which starts off hot, then cools; then gets hot again, and cools again...and on and on...

Whenever it is mentioned that Gravity halts the expansion of the universe, this is referring to the fact the "Dark Energy”, which causes Space-time expansion, becomes diluted, and loses its grip. When the expanding "Dark Energy" becomes diluted, and loses its grip, it finally becomes weak enough to allow the matter and the Gravitational Energy to become strong. Eventually "Gravity" will be able to clump matter together in the form of galaxies. This "Gravity" will continue to pull all matter into a single clump and form one big blob of mass.

With Gravity acting alone without the grips of the expanding “Dark Energy”, this could conceivably continue to condense all the matter in the universe forming a Universal "Black Hole" or new Epoch, which would get so hot and dense it would create a new bang, and begin to expand once again. Once, all matter is condensed and forms one big blob of mass; this restarts the process and the Dark Energy wins over Inertial Mass Gravity; and starts the whole process over again.

Once again, this is total speculation, and is meant for discussion. I am not sure if I agree with this scenario; however this is possible.
 
  • #13
Sup_Principia said:
Whenever it is mentioned that Gravity halts the expansion of the universe, this is referring to the fact the "Dark Energy”, which causes Space-time expansion, becomes diluted, and loses its grip.
Just bear in mind that for this to happen, the dark energy would have to radically change its behavior. The most likely situation is that it will continue acting as it has up to now, which means continued acceleration indefinitely. This, in turn, means a heat death.
 
  • #14
Chalnoth said:
Just bear in mind that for this to happen, the dark energy would have to radically change its behavior. The most likely situation is that it will continue acting as it has up to now, which means continued acceleration indefinitely. This, in turn, means a heat death.

Based on your post, you obviously accept that the universe ends up in a "Heat Death" this is perfectly ok.

But the original post (OP) asked the question

Delong said:
... heat death ... Is this true and is it inescapable? What can we perhaps do about it?

So the answer is that a "Big Bounce" or an "Oscillatory Universe" model allows us to escape the inescapable "Heat Death"


This is speculation only based on the (OP)'s question:

However, the "Dark Energy" would not have to, as you put it, radically change its behavior. The "Dark Energy" is doing what it is suppose to do, expand Space-time in the presence of matter. And Inertial Mass Gravity is doing what it is suppose to do. Cause Inertial Matter/Mass to clump together.

What this model would suggest is that there is another Force and Energy out there that counter acts the "Dark Energy" over long distances. I propose that this energy is called the "Heat Radiation Gravitation" energy of space-time. The "Heat Radiation Gravitation" energy would cause the expanding "Dark Energy" to become diluted, and loses its grip, and finally becomes weak over great distances.

Once again, this is total speculation, however, there is some evidence for the above, and is meant for discussion.
 
  • #15
Darn...
that really sucks.
 
  • #16
Delong said:
Darn...
that really sucks.

What really sucks?
 
  • #17
Sup_Principia said:
What this model would suggest is that there is another Force and Energy out there that counter acts the "Dark Energy" over long distances. I propose that this energy is called the "Heat Radiation Gravitation" energy of space-time. The "Heat Radiation Gravitation" energy would cause the expanding "Dark Energy" to become diluted, and loses its grip, and finally becomes weak over great distances.

Once again, this is total speculation, however, there is some evidence for the above, and is meant for discussion.

Please reread the forum's rules (which you have agreed to when you joined) on overly speculative posts.
 
  • #18
Sup_Principia said:
What really sucks?

That heat death is most probably inevitable.
 
  • #19
Delong said:
That heat death is most probably inevitable.
If it makes you feel better, it probably won't happen before you die of old age.
 
  • #20
bcrowell said:
Please reread the forum's rules (which you have agreed to when you joined) on overly speculative posts.

However, here is some evidence for a peer reviewed article on the subject. And this takes the "Big Bounce" model out of complete speculation; and therefore no forum rule is violated. I have read all of the rules for posting on this forum, and do completely comply.

http://www.newscientist.com/article...nce-cosmos-makes-inflation-a-sure-thing.html"
 
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  • #21
Hurkyl said:
If it makes you feel better, it probably won't happen before you die of old age.

It does a little...still it's kind of sad sometimes. I'm so glad I'm religious hahahaha...
 
  • #22
Sup_Principia said:
So the answer is that a "Big Bounce" or an "Oscillatory Universe" model allows us to escape the inescapable "Heat Death"
Yes, but again, that requires a model radically different than the simplest model that fits observation.

Sup_Principia said:
This is speculation only based on the (OP)'s question:

However, the "Dark Energy" would not have to, as you put it, radically change its behavior. The "Dark Energy" is doing what it is suppose to do, expand Space-time in the presence of matter. And Inertial Mass Gravity is doing what it is suppose to do. Cause Inertial Matter/Mass to clump together.

What this model would suggest is that there is another Force and Energy out there that counter acts the "Dark Energy" over long distances. I propose that this energy is called the "Heat Radiation Gravitation" energy of space-time. The "Heat Radiation Gravitation" energy would cause the expanding "Dark Energy" to become diluted, and loses its grip, and finally becomes weak over great distances.

Once again, this is total speculation, however, there is some evidence for the above, and is meant for discussion.
This is a model that is radically different from the simplest one that fits observation, and involves dark energy that behaves radically different in the future than it has up to now.

Oh, and "heat radiation gravitation" makes no sense.
 
  • #23
Delong said:
That heat death is most probably inevitable.
Why does that suck? If the dark energy is truly a cosmological constant, then the universe will approach a small but non-zero temperature in the far future. This non-zero temperature means that there will be quantum fluctuations that will produce new regions of space-time periodically within our own. A heat death universe is not the end except in the sense that it is the end of our universe. A recollapse scenario would just bring about the end of our universe more rapidly.
 
  • #24
Sup_Principia said:
I knew that "You" personally were coming after me! I know your type! You were watching everyone of my post, just waiting for an opportunity to throw some kind of a rock. That is why I continued to refer back to the original post (OP)'s question. Which could not be answered without speculation.

However, here is some evidence for a peer reviewed article on the subject. And this takes the "Big Bounce" model out of complete speculation; and therefore no forum rule is violated. I have read all of the rules for posting on this forum, and do completely comply.

http://www.newscientist.com/article...nce-cosmos-makes-inflation-a-sure-thing.html"

I don't see any correlation between the "Heat Radiation Gravitation" material in your #14 and the New Scientist article you linked to. The New Scientist is not a peer-reviewed journal. The OP can be discussed without violating PF's rules on overly speculative posts.

-Ben
 
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  • #25
bcrowell said:
I don't see any correlation between the "Heat Radiation Gravitation" material in your #14 and the New Scientist article you linked to. The New Scientist is not a peer-reviewed journal. The OP can be discussed without violating PF's rules on overly speculative posts.

-Ben

You are right the article does not mention the term "Heat Radiation Gravitation" The article mentions "Superinflation", which in my opinion gives a better interpretion of the term "Superinflation."

You are correct the New Scientist is not a peer-reviewed journal, but in the article they reference peer reviewed papers:

Article: http://www.newscientist.com/article...nce-cosmos-makes-inflation-a-sure-thing.html"

Physical Review D - http://prd.aps.org/abstract/PRD/v77/i6/e063516" Physics Letters B - http://www.sciencedirect.com/science/article/pii/S0370269310011585"
 
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  • #26
Chalnoth said:
Why does that suck? If the dark energy is truly a cosmological constant, then the universe will approach a small but non-zero temperature in the far future. This non-zero temperature means that there will be quantum fluctuations that will produce new regions of space-time periodically within our own. A heat death universe is not the end except in the sense that it is the end of our universe. A recollapse scenario would just bring about the end of our universe more rapidly.

Chalnoth, can you provide any supporting material for your speculative ideas?
 
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  • #27
Sup_Principia said:
You are right the article does not mention the term "Heat Radiation Gravitation" The article mentions "Superinflation", which in my opinion gives a better interpretion of the term "Superinflation."

The article has nothing to do with the speculative material in your #14. Please calm down.
 
  • #28
bcrowell said:
The article has nothing to do with the speculative material in your #14.

Since you are making it sound like you understand the "SuperInflation" concept as described in the article. Then explain what you think the article means by "SuperInflation" in regards to the "Big Bounce" theory; which would act in contradiction to a "Heat Death" model of the universe; which is based on the original post (OP)'s question??

Answering this question is what is called, engaging in physics!
 
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  • #29
Sup_Principia said:
This appears highly speculative.
Only in the sense of proposing that the dark energy truly is a cosmological constant. But then that's not so much speculative as it is the simplest explanation that fits the data. Anyway, here's a paper that went into this in a fair amount of detail:
http://arxiv.org/abs/hep-th/0410270
 
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  • #30
Chalnoth said:
Only in the sense of proposing that the dark energy truly is a cosmological constant. But then that's not so much speculative as it is the simplest explanation that fits the data. Anyway, here's a paper that went into this in a fair amount of detail:
http://arxiv.org/abs/hep-th/0410270


Chalnoth, you mention that the dark energy truly is a cosmological constant. The speed of light in a vacuum is a cosmological constant. Are you supposing that the dark energy is truly is a cosmological constant, like the speed of light in a vacuum?

Are you stating that the Dark Energy has the same value throughout the universe? If this is true where is this found in litererature??

And what is the math that describes this dark energy cosmological constant?
 

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