Why did entropy decrease after the big bang?

In summary, the cosmic microwave background radiation shows that the energy of the universe was very uniform at one point, however, as galaxies were formed, the energy became more diverse. This could be because the less-diverse spaces/time are less stable and have a lower entropy.
  • #1
pointlesslife
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According to the big bang model, the very early universe was at one time filled with energy. The cosmic microwave background radiation shows that the energy of the universe was very uniform. The deviation of energy in the famous CMB radiation picture taken was on average just 1 in 100,000 the average temperature.

So why did uniformity decrease as galaxies were formed in the very early universe? Does this contradict the 2nd law of thermodynamics?
 
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  • #2
Contrary to popular opinion, uniformly distributed matter is unstable in presence of gravitation and is actually the least likely state with very low entropy. Most probable high-entropy states are those where matter is all lumped together in massive objects, culminating in the creation of black holes.
 
  • #3
Delta Kilo said:
Contrary to popular opinion, uniformly distributed matter is unstable in presence of gravitation and is actually the least likely state with very low entropy. Most probable high-entropy states are those where matter is all lumped together in massive objects, culminating in the creation of black holes.

Now that I think about it, gravitation does turn the tables. It would be impossibly improbable for objects such as planets/stars to uniformly distribute back in space again. So yeah, I would agree that entropy of the early universe was very low and has only increased since so the 2nd law of thermodynamics isn't wrong.
 
  • #4
Consider that all matter and energy in the early universe was closer together than it is now. But at the same time moving away from the center.

Entropy might have a dependence on the curve of space/time, as the less curve the more entropy. So matter and energy that are not as close together have a lower gravity and thus appear to the observer to be unstable and a low entropy. But the higher density space/time with the matter and energy closer together has a higher entropy. It could be then that distance has a lot to do with it along with gravity and space/time as factors. In higher energy states we find that space/time can separate into space and time.

Your automotive engine for example is density packed with metals and uses high energy or heat from explosions of gasoline to push pistons and give you the ability to turn the wheels. In this high energy state, we have high energy but we still have Earth's gravity as well as high entropy. Which is why your fuel efficiency goes down so heat is a form of energy that has to do with it.

Then I'd say that stars generate heat to cause higher entropy and in the early universe there wasn't much heat as stars didn't form yet and provide the heat and higher gravity for higher entropy.

Just a theory, I could be wrong.
 
  • #5


I can provide a scientific explanation for the decrease in entropy after the big bang. The concept of entropy is closely related to the second law of thermodynamics, which states that the total entropy of a closed system always increases over time. However, this law applies to isolated systems, and the universe is not an isolated system.

During the big bang, the universe was in a state of extreme density and energy. As the universe expanded and cooled, this energy was converted into matter, and the universe became less chaotic and more structured. This decrease in chaos and increase in structure is the reason for the decrease in entropy.

The formation of galaxies and other structures in the early universe may seem to contradict the second law of thermodynamics, but it is important to remember that the universe is an open system. It is constantly exchanging energy and matter with its surroundings, allowing for local decreases in entropy while the total entropy of the universe continues to increase.

Furthermore, the decrease in entropy after the big bang was not a sudden event, but a gradual process that occurred over billions of years. This gradual decrease in entropy is consistent with the second law of thermodynamics.

In summary, the decrease in entropy after the big bang can be explained by the expansion and cooling of the universe, the conversion of energy into matter, and the fact that the universe is an open system. This does not contradict the second law of thermodynamics, but rather, it is a manifestation of it in a complex and dynamic system like the universe.
 

FAQ: Why did entropy decrease after the big bang?

Why did entropy decrease after the big bang?

Entropy is a measure of disorder or randomness in a system. After the big bang, the universe began as a highly ordered and dense state. As the universe expanded, this order started to break down, leading to an increase in entropy. However, at some point, the universe began to cool and form structures, which led to a decrease in entropy.

What caused the decrease in entropy after the big bang?

The decrease in entropy after the big bang can be attributed to the fundamental forces of nature, specifically gravity. As the universe expanded and cooled, gravity began to pull matter together, leading to the formation of stars, galaxies, and other structures. This process of gravitational collapse and condensation increased the level of order and decreased entropy in the universe.

How does the decrease in entropy after the big bang relate to the second law of thermodynamics?

The second law of thermodynamics states that the total entropy of a closed system always increases over time. However, this law does not apply to the entire universe as a closed system. The decrease in entropy after the big bang is a result of the universe's expansion and the formation of structures, which is not a closed system. Therefore, the decrease in entropy after the big bang is not in violation of the second law of thermodynamics.

Was the decrease in entropy after the big bang necessary for the formation of life?

There is no definitive answer to this question. Some scientists argue that a decrease in entropy was necessary for the formation of life, as it allowed for the development of complex structures and the emergence of biological processes. However, others argue that life can exist even in highly chaotic and disordered systems, so the decrease in entropy after the big bang may not be a necessary condition for life to arise.

Will entropy continue to decrease in the future?

It is currently unknown what will happen to entropy in the future. Some theories suggest that the universe will continue to expand and cool, leading to a decrease in entropy and the eventual "heat death" of the universe. However, other theories suggest that the universe may reach a maximum level of entropy and then start to decrease again. Further research and observations are needed to understand the fate of entropy in the future.

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