How Can New Stars Form from Chaos While Entropy Increases?

AI Thread Summary
The discussion centers on the second law of thermodynamics, which states that entropy in the universe is always increasing, raising questions about how gravity can lead to the formation of stars from chaotic supernova remnants, seemingly decreasing local entropy. Participants debate the definition of "the whole universe," questioning whether it is a closed or open system and emphasizing the importance of focusing on observable phenomena. The conversation highlights that while black holes represent the highest entropy state, the entropy of stars and their emitted radiation compared to gas remains unclear and requires further qualification. There is also speculation about the complexities of entropy in systems influenced by gravitational forces, suggesting that traditional understandings of entropy may not apply uniformly. Overall, the discussion reveals the nuanced relationship between gravity, entropy, and the formation of cosmic structures.
yasar1967
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According to the second law of TD, entropy is increasing in the whole universe.
Then how could you explain the fact that from a chaotic state of dust and gas remnants of a supernova, gravity causes all them to gather together to form new stars which are less chaotic thus having less entropy than the former state?
And this happens ALL THE TIME through t the universe.
 
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Local entropy can decrease for various reasons, but there is always a corresponding increase in the larger system.

What do you mean by "the whole universe?" Last I checked, no one knew for sure if there is such a thing. Is the universe a closed system? Or an open one?

It is probably better when learning physics to stick to observable phenomena, and "the whole universe" is not observable.
 
I think you'll find it said (in the published literature) that the highest entropy state is the black hole (consider the no hair theorem versus the number of unknowable microstates), and that homogeneously distributed dust is not very chaotic.
 
Are you sure stars and the radiation they emit have less entropy than the gas they originate from? You will probably need to qualify this assertion a little better because it isn't obvious to me that this is true.

Claude.
 
I suspect it's a superficial thing, "entropy" isn't always visible in the same manner. In an ideal gas (with particles uncoupled from each other), the most probable macro-state is well known to be the least clumped and most uniform. Throw in the force of gravitational interactions and that result is just no longer the case (the uniform distribution is balanced in unstable equilibrium). Wonder if there is a similar "paradox" with ferromagnetism vs diamagnetism?
 
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