<p>Heat death of the Universe doesn't mean that there is no energy in it, it means it has reached thermodynamic equilibrium and hence no useful energy in it. This could in theory occur in an infinite Universe.</p>

<p>Of course thermodynamics is statistical in nature, so an argument could be made that some extremely unlikely event in a region of the Universe could destroy thermal equilibrium in that region and that the larger the Universe the more likely that some region like that exists.</p>

CC BY-SA 3.0
2015-11-20T21:06:27.200Z
Good answer, but remember that I specifically said "free energy".
Sir Cumference
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2015-11-20T21:09:00.147Z
Apologies - read your question a little too quickly
John Davis
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2015-11-20T20:25:57.343Z
2015-11-20T20:25:57.343Z
John Davis
<p>If the Universe is infinite, one would imagine that if we kept moving through space, we'd constantly find newer and newer galaxies and objects forever. This would imply that there is an infinite amount of matter in the Universe.</p>

<p>The heat death theory states that, eventually, there will be no free energy left in the Universe. Stars would no longer form, black holes would eventually evaporate, and the Universe would be effectively dead. But if there's an infinite amount of matter, won't there always be more gas clouds that haven't formed stars, more stars that have yet to become black holes, etc.? If there is an infinite amount matter and energy, shouldn't more activity be possible no matter how many stars go out or how many black holes evaporate?</p>

<p>One might say that with enough time, all matter in the Universe would still run dry. But if there is an <em>infinite</em> amount, there should always be areas in which activity is still going on...right?</p>

<p>Is what I'm saying correct? Does the heat death of the Universe contradict the theory that it is infinite?</p>

CC BY-SA 4.0
2021-12-19T00:19:19.847Z
Some infinites are bigger than other infinites. I'm not a mathematician but my hunch is that if you haven't infinite amount of material with half lives eventually it'll all be gone. I recall back in the day that there's some formulas of a tube that is infinitely long that has a finite volume. So again just because something is infinity doesn't it mean it is the end all
Bob Matulis
CC BY-SA 3.0
2015-11-20T00:52:28.123Z
The first two sentences use circular logic. You'd only continue finding matter if there was an infinite amount of matter - which can't be assumed.
HDE 226868
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2015-11-20T12:46:05.443Z
No-one says the universe is infinite. In fact most theories state it can't be.
Rory Alsop
CC BY-SA 3.0
2015-11-20T12:50:38.193Z
@RoryAlsop Au contraire, many theories (like the standard ΛCDM model of the Big Bang) state that the Universe is infinite.
Sir Cumference
CC BY-SA 3.0
2015-11-20T12:55:18.800Z
But not infinite in that way, just endless
Rory Alsop
CC BY-SA 3.0
2015-11-20T23:27:08.560Z
If eternal inflation is correct, then there will always be some chunk of spacetime, somewhere, sometime, that is just undergoing inflation anew. So the universe as a whole would never die, just the chunk within your event horizon. (I am grossly over-simplifying, sorry)
Florin Andrei
CC BY-SA 3.0
2015-11-21T01:42:47.093Z
If the universe is going to last an infinitely long time, won't every possible thing that could arise from the quantum foam occur? Including another big bang? And in an infinite amount of time, wouldn't it occur over and over? Further, wouldn't the events that devolve from one big bang eventually duplicate the events of a previous big bang?
Howard Miller
<gravity><universe><dark-energy><fate-of-universe>
If the Universe is infinite, would heat death be impossible?
Sir Cumference
# If the Universe is infinite, would heat death be impossible?

(Asked by: username_0 on 2015-11-20)

If the Universe is infinite, one would imagine that if we kept moving through space, we'd constantly find newer and newer galaxies and objects forever. This would imply that there is an infinite amount of matter in the Universe.

The heat death theory states that, eventually, there will be no free energy left in the Universe. Stars would no longer form, black holes would eventually evaporate, and the Universe would be effectively dead. But if there's an infinite amount of matter, won't there always be more gas clouds that haven't formed stars, more stars that have yet to become black holes, etc.? If there is an infinite amount matter and energy, shouldn't more activity be possible no matter how many stars go out or how many black holes evaporate?

One might say that with enough time, all matter in the Universe would still run dry. But if there is an *infinite* amount, there should always be areas in which activity is still going on...right?

Is what I'm saying correct? Does the heat death of the Universe contradict the theory that it is infinite?

**Tags:** gravity, universe, dark-energy, fate-of-universe

> **Comments:**
> **username_2**: The first two sentences use circular logic. You'd only continue finding matter if there was an infinite amount of matter - which can't be assumed.  
> **username_3**: No-one says the universe is infinite. In fact most theories state it can't be.  
> **username_0**: @username_3 Au contraire, many theories (like the standard ΛCDM model of the Big Bang) state that the Universe is infinite.  
> **username_3**: But not infinite in that way, just endless  
> **username_4**: If eternal inflation is correct, then there will always be some chunk of spacetime, somewhere, sometime, that is just undergoing inflation anew. So the universe as a whole would never die, just the chunk within your event horizon. (I am grossly over-simplifying, sorry)  
> **username_5**: If the universe is going to last an infinitely long time, won't every possible thing that could arise from the quantum foam occur? Including another big bang? And in an infinite amount of time, wouldn't it occur over and over? Further, wouldn't the events that devolve from one big bang eventually duplicate the events of a previous big bang?  
> **username_1**: Some infinites are bigger than other infinites. I'm not a mathematician but my hunch is that if you haven't infinite amount of material with half lives eventually it'll all be gone. I recall back in the day that there's some formulas of a tube that is infinitely long that has a finite volume. So again just because something is infinity doesn't it mean it is the end all  

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## 1 answers

### Answer by username_6 on 2015-11-20. Score: 3 | Accepted answer

Heat death of the Universe doesn't mean that there is no energy in it, it means it has reached thermodynamic equilibrium and hence no useful energy in it. This could in theory occur in an infinite Universe.

Of course thermodynamics is statistical in nature, so an argument could be made that some extremely unlikely event in a region of the Universe could destroy thermal equilibrium in that region and that the larger the Universe the more likely that some region like that exists.

> **Comments:**
> **username_0**: Good answer, but remember that I specifically said "free energy".  
> **username_6**: Apologies - read your question a little too quickly  

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