The Scale Factor & Universe Entropy: Examining Heat Death

AI Thread Summary
The discussion explores the relationship between the universe's scale factor and entropy, specifically addressing the implications of exponential expansion on heat death and thermal equilibrium. It posits that while the scale factor increases, the atomic forces will initially dominate, preventing significant structural changes in galaxies and atoms. However, as time progresses, the exponential growth of the scale factor could eventually overpower these forces, leading to a scenario where heat cannot flow and a Big Rip occurs. The conversation highlights the tension between the concepts of heat death and the Big Rip, suggesting that heat death may not be a primary concern in such a scenario. Ultimately, the future of the universe remains uncertain as these dynamics unfold.
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Empirical evidence supports that the scale factor is proportional to the following.

a(t) = e^(HT)

Where the distance between any two objects are

D(t) = a(t)Δx

Where x does not measure physical distance, but a conventional coordinate distance.

This means that eventually any physical distance (Even quantum wavelengths) will grow exponentially and eventually a big rip will happen. My question is how can the universe truly reach heat death or thermal equilibrium if its going to expand so fast in the far future? My intuition tells me that it will asymptotically approach maximum entropy.
 
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The effect of exponential growth of the scale factor will be negligible at the everyday scale. So I believe even though the distance between objects will keep increasing, the structures in the universe, galaxies and atoms etc would not be greatly affected. Of course the size of the atom would be slightly larger now but it won't break off. At those scales the atomic forces will be dominant.
 


Avijeet said:
The effect of exponential growth of the scale factor will be negligible at the everyday scale. So I believe even though the distance between objects will keep increasing, the structures in the universe, galaxies and atoms etc would not be greatly affected. Of course the size of the atom would be slightly larger now but it won't break off. At those scales the atomic forces will be dominant.

At first you may be correct, but the scale factor is exponentially growing. As t approaches infinity, a will become so great, it will eventually overwhelm the atomic forces.
 


I don't think heat death is the case (or the major concern, for that matter) in a Big Rip scenario. The observable universe of every particle would shrink much, much faster than the speed of light, so, heat cannot flow. You should search for both terms (Heat death and Big Rip) on Wikipedia; the articles are pretty good.
 
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