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Old Jul 24th 2015, 03:05 AM   #1
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Predicted Heat Death of the Universe

Predicted Heat Death of the Universe

In his thought provoking documentary “Wonder of the universe” (
) Professor Brian Cox explains the thinking behind current predictions for the “Heat death of the universe”. He explains the predictions through the effect of the second law of thermodynamics whereby the universe gradually moves from an ordered state (low entropy) to a state of disorder (high entropy). He states:

“The last remaining matter in the universe will reside within black dwarves. We can predict how they will end their days. The last matter of the universe will evaporate away and be carried off into the void as radiation leaving absolutely nothing behind.

There won’t be a single atom left; all that’s left will be particles of light and black holes. After an unimaginable period even the black holes will have evaporated; the universe will be nothing but a sea of photons gradually tending to the same temperature as the expansion of the universe cools them towards absolute zero.

The story of the universe will come to an end. For the first time in its life the universe will be permanent and unchanging. Entropy will finally stop increasing because the cosmos cannot get any more disordered. Nothing happens and it keeps not happening for ever. There is no difference between past present and future, nothing changes, arrow of time has simply ceased to exist.

It is an inescapable fact written into the laws of physics that entire cosmos will die; all the stars will go out extinguishing possibility of life in the universe.”


Reconciling the predicted Heat Death of the Universe with the initial state

The assumption seems to be that the singularity from which the universe is thought to have arisen was an ordered state (low entropy) and that since the big bang the entropy is increasing with the inevitable end result that all matter will be converted to energy which will then cool to absolute zero after which entropy will be at its maximum value and nothing will occur in the universe.

The predictions appear to be correct according to the second law of thermodynamics. One can imagine an ever expanding universe whereby all its heat energy is dissipated until it reaches absolute zero temperature whereupon all events will cease.

There are fundamental difficulties in accepting this end state of the universe.

Firstly it is extremely depressing and counter intuitive for humans to envisage a universe in which there is no possibility of life and where no events will ever occur. However this difficulty does not preclude such an end state of the universe.

The second and more important difficulty in accepting this end state is in reconciling the predicted end state of the universe with the currently accepted initial conditions of the universe prior to the big bang.

The initial conditions of the universe prior to the big bang are assumed to be a singularity of infinite density and zero volume which according to the second law of thermodynamics would be considered to be a highly ordered state with low entropy. The question arises as to how the singularity came to be in this state and what caused it to suddenly expand so rapidly into the observable universe.

The singularity can only have been in existence for a finite period of time as otherwise it could not have suddenly expanded.

As in the predicted end state of the universe at a temperature of absolute zero no events can occur without events to precipitate such events.

Assuming the singularity to be an enclosed system with nothing outside (no space, no matter, no energy, no events) the expansion can only have occurred as a result of events within the singularity. Alternatively assuming no events inside the singularity the expansion can only have occurred as a result of events outside the singularity.

There is a finite number for all the possible permutations of events that could have precipitated the expansion. It follows that there must have been events prior to the existence of the singularity as a singularity. In other words the singularity must have come into existence from a previous state of its contents.

Assuming a finite amount of material within the singularity (and the previous states of the singularity) all possible permutations of events including the sequence of events in our current universe constituting the predicted “Heat Death of the universe” would have already occurred prior to the big bang.

From this it follows that either the predicted “Heat Death of the universe” is not possible or that it is predicated on an incorrect set of data or that the second law of thermodynamics is incomplete.

Last edited by jonathancollins; Jul 24th 2015 at 03:42 AM. Reason: Mistake
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Old Jul 24th 2015, 03:24 AM   #2
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The assumption seems to be that the singularity from which the universe is thought to have arisen was an ordered state (high entropy) and that since the big bang the entropy is diminishing with the inevitable end result that all matter will be converted to energy which will then cool to absolute zero after which entropy will be at its minimum value and nothing will occur in the universe.
Before proceeding further, please check you have this the right way round.

The Entropy of an isolated system can never decrease.
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Old Jul 24th 2015, 05:17 AM   #3
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I agree with your analysis, but...

I also find myself persistently mixing up the direction of entropy,
I think that the natural tendency is to imagine things starting high and then running down hill.

Putting that aside,
The concept of time , and even of causality, fails before the start of the universe (and also after the heat death end of the universe).
One has to start thinking of what is "outside" of the universe, a kind of metaverse if you will.

My personal idea is a kind of probability proposal.
Anything that CAN happen, happens.
Thus the universe existing is ridiculously unlikely, but crucially not impossible.
There are likely other self consistent existences that are not impossible
and therefore (by my first postulate) must exist.
In this scenario I would suggest that the most probable situation would be nothing existing, with very small (but non-zero) possibilities of various somethings.

Coming back to this universe, we start with a hugely improbable big-bang, (low entropy)
and progress to the much more probable "nothing" of the heat death (high entropy)
This defines the time-wise dimension of the universe.
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Old Jul 24th 2015, 05:29 AM   #4
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Hello you say that pre/extra universe 'nothing' existed, yet possibilities existed?

Does not the existence of possibilities mean something existed?
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Old Jul 24th 2015, 06:19 AM   #5
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Originally Posted by jonathancollins
The second and more important difficulty in accepting this end state is in reconciling the predicted end state of the universe with the currently accepted initial conditions of the universe prior to the big bang.
...
The initial conditions of the universe prior to the big bang are assumed to be a singularity of infinite density and zero volume which according to the second law of thermodynamics would be considered to be a highly ordered state with low entropy. The question arises as to how the singularity came to be in this state and what caused it to suddenly expand so rapidly into the observable universe.
If we call the instant of the Big Bang t=0, cosmologists know absolutely nothing about the "state" of the singularity at t=0. About as close to t=0 that anyone had been able to model is about t= 10^(-32) seconds. And they certainly know nothing about what may have existed prior to t=0. In fact, it's not clear that time even existed prior to t=0. So discussions about the state of the universe prior to the Big Bang are meaningless. It's a bit like asking about what's north of the north pole.

And yes, I agree, it's a very depressing prediction!

Last edited by ChipB; Jul 24th 2015 at 08:30 AM.
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Old Jul 24th 2015, 07:16 AM   #6
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Originally Posted by studiot View Post
Hello you say that pre/extra universe 'nothing' existed, yet possibilities existed?

Does not the existence of possibilities mean something existed?
Terminology does become a bit difficult in the metauniverse...

However saying something is impossible is not (exactly) the same as saying it doesn't exist, it is saying it CANNOT exist.
The corollary of this is that something that CAN exist MUST exist.

However it is not correct to talk of these alternative existences being before or after or even simultaneous to our universe.
Similarly there is no causal connection between them.
They just are possible, or they aren't possible.
If they are possible, then what mechanism would be put forward to favour or hinder their existence relative to the existence of our own dear little universe.
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Old Jul 24th 2015, 07:31 AM   #7
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Terminology does become a bit difficult in the metauniverse...
Can be a bit awkward in the real universe around us as well.

Take for instance the following proof that 'nothing' exists.

Take two (identical) solid objects (even a 2D one if you wish) and bore a hole right through one of them.

The objects are now different and have demonstrably different mathematical and physical properties.

Yet the only difference is the hole, which is made of nothing.

Therefore nothing exists.
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Old Jul 24th 2015, 08:34 AM   #8
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Originally Posted by MBW View Post
I also find myself persistently mixing up the direction of entropy,
I think that the natural tendency is to imagine things starting high and then running down hill.

Putting that aside,
The concept of time , and even of causality, fails before the start of the universe (and also after the heat death end of the universe).
One has to start thinking of what is "outside" of the universe, a kind of metaverse if you will.

My personal idea is a kind of probability proposal.
Anything that CAN happen, happens.
Thus the universe existing is ridiculously unlikely, but crucially not impossible.
There are likely other self consistent existences that are not impossible
and therefore (by my first postulate) must exist.
In this scenario I would suggest that the most probable situation would be nothing existing, with very small (but non-zero) possibilities of various somethings.

Coming back to this universe, we start with a hugely improbable big-bang, (low entropy)
and progress to the much more probable "nothing" of the heat death (high entropy)
This defines the time-wise dimension of the universe.
Hi MBW,

How do you conclude that "The concept of time , and even of causality, fails before the start of the universe (and also after the heat death end of the universe)."?
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Old Jul 24th 2015, 08:42 AM   #9
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Originally Posted by studiot View Post
Can be a bit awkward in the real universe around us as well.

Take for instance the following proof that 'nothing' exists.

Take two (identical) solid objects (even a 2D one if you wish) and bore a hole right through one of them.

The objects are now different and have demonstrably different mathematical and physical properties.

Yet the only difference is the hole, which is made of nothing.

Therefore nothing exists.
There are flaws in your argument:

1. A 2D object cannot exist other than in the imagination

2. A hole in an object consists of space (ether if you will) and potentially various forms of energy but certainly not "nothing"

The existence of the universe rules out the existence of "nothing" as the 2 states are mutually exclusive.
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Old Jul 24th 2015, 08:48 AM   #10
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Originally Posted by ChipB View Post
If we call the instant of the Big Bang t=0, cosmologists know absolutely nothing about the "state" of the singularity at t=0. About as close to t=0 that anyone had been able to model is about t= 10^(-32) seconds. And they certainly know nothing about what may have existed prior to t=0. In fact, it's not clear that time even existed prior to t=0. So discussions about the state of the universe prior to the Big Bang are meaningless. It's a bit like asking about what's north of the north pole.

And yes, I agree, it's a very depressing prediction!
Hi CHIPB,

How do you conclude that "time may not have existed prior to t=0"?
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