The Scale Factor & Universe Entropy: Examining Heat Death

[zeromodz]

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.

 

[Avijeet]

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.

 

[zeromodz]

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.

 

[Oscuro93]

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.

 

[sardar]

Thank you for your question. The concept of heat death, also known as the "big freeze," is based on the idea that the universe will eventually reach a state of maximum entropy, where all energy is evenly distributed and no work can be done. This is supported by the second law of thermodynamics, which states that entropy (or disorder) in a closed system will always increase over time.

The scale factor and universe entropy are intertwined in this concept of heat death. As the universe expands, the scale factor increases and the distance between objects grows. This leads to a decrease in the density of matter and energy, resulting in a decrease in the available energy for work. Eventually, the universe will reach a point where all matter is so spread out that it can no longer interact and do work, leading to a state of thermal equilibrium.

However, it is important to note that this is a theoretical concept and there are still many unknowns about the future of the universe. The scale factor and universe entropy are not the only factors that will determine the fate of the universe. Other factors, such as the nature of dark energy and the curvature of space-time, also play a role.

In addition, the rate of expansion of the universe is not constant and can be affected by various factors, such as the distribution of matter and energy. It is possible that the expansion of the universe could slow down or even reverse in the far future, leading to a different outcome than the big freeze.

In conclusion, while the concept of heat death is based on empirical evidence and theoretical models, there are still many uncertainties and unknowns about the future of the universe. As scientists, it is important to continue studying and exploring these concepts in order to gain a better understanding of the fate of our universe.