Gravity vs Entropy: Heat Distribution in Matter-Free Space?

[mosarani]

From what I understand of the second law of thermodynamics, the tendency for overall entropy to increase is unstoppable; for entropy to decrease locally it must increase globally. But the force of gravity keeps matter throughout the cosmos in chunks, not uniformly spread out.

My question is: Since temperature is a measure of atomic excitement, how can energy move towards a uniform distribution in places where there are no atoms? If gravity keeps matter in discrete chunks how can heat be evenly distributed where there is no matter to hold that heat?

 

[Aaron Barnard]

The second law of thermodynamics does not necessarily require that energy move towards uniformity in all places. It simply states that the entropy of an isolated system will tend to increase over time, meaning that any given system, if left to its own devices, will become more disordered and chaotic. This could mean that energy becomes more evenly distributed, but it could also mean that pockets of higher energy become further concentrated.

In terms of empty space, there is still energy present. This energy can be in the form of radiation, such as light and heat, which can travel through space even in the absence of matter. This radiation can cause particles to become excited and move around, eventually leading to a more uniform distribution of energy.

 

[astrokreng]

I can provide some insights into this question. First, it is important to note that the second law of thermodynamics applies to closed systems, meaning that there is no external energy or matter entering or leaving the system. In the case of matter-free space, it can be considered a closed system as there is no matter or energy entering or leaving.

Now, let's consider the role of gravity in this scenario. Gravity is a force that acts on matter, causing it to clump together into chunks. This is why we see planets, stars, and other celestial bodies in the universe. In the absence of gravity, matter would be evenly distributed throughout space.

So, in a matter-free space, there is no gravity to clump matter together and create uneven distribution. However, there are other forces at play that can lead to uneven distribution of energy. For example, electromagnetic radiation, such as light, can transfer energy even in the absence of matter. This means that even in a matter-free space, there can be areas with higher energy and areas with lower energy, leading to an overall uneven distribution.

Additionally, it is important to note that temperature is not just a measure of atomic excitement, but also a measure of the average kinetic energy of particles in a system. In a matter-free space, there may not be atoms, but there can still be particles such as photons, which have kinetic energy and can contribute to the overall temperature of a region.

In summary, while gravity plays a significant role in the distribution of matter in the universe, other forces such as electromagnetic radiation can also contribute to the distribution of energy in a matter-free space. The second law of thermodynamics still applies, but it may manifest in different ways in the absence of matter.