B Does gravity defy the 2nd Law?

Click For Summary
The discussion explores the relationship between gravity, thermodynamics, and entropy, questioning whether gravity can defy the second law of thermodynamics. It is clarified that gravity does not violate this law, as the second law applies to isolated systems, and a star's formation involves energy loss through radiation. A burning star is determined to be a higher entropy state than the initial gas cloud due to its higher temperature and the larger phase space it occupies. The conversation also touches on the conditions necessary for gravitational collapse, emphasizing that energy dissipation is crucial for such processes to occur. Ultimately, the consensus is that gravitational collapse can lead to increased entropy, contrary to initial assumptions about the order of the gas cloud.
  • #31
Perhaps an image is worth more than 100 words. This is my intuitive picture

Gravity and 2nd Law.JPG
 
  • Like
Likes Demystifier and vanhees71
Science news on Phys.org
  • #32
Gerinski said:
I never stated that the cloud of gas could or could not radiate, that came only in some of the answers such as Anorlunda's.
You are the one who put it in the container, from which it can't radiate.
Personally, even now I do not see why such a gravitationally coalescing cloud of gas could not radiate to its immediate environment in the rest of the container.
What "rest of the container? Isn't it filled completely with a gas?

How does your scenario apply to the real universe? Why are we even talking about it? What game are we playing here?
 
Last edited:
  • #33
Gerinski said:
I never stated that the cloud of gas could or could not radiate
Gerinski said:
Because of the impossibility to radiate

In general, if you are going to do that, it's best to do it somewhere where your previous messages are not stored.

And I'm done here.
 
  • Like
Likes russ_watters and berkeman
  • #34
The answer was given by @Demystifier in post #6: the wrong assumption is that entropy has been reduced.

Time to close the thread. Thanks to all that participated.
 
  • Like
Likes russ_watters, PeroK and Demystifier

Similar threads

Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
Replies
6
Views
1K
  • · Replies 152 ·
6
Replies
152
Views
10K
Replies
8
Views
2K
Replies
1
Views
6K
  • · Replies 11 ·
Replies
11
Views
2K
Replies
7
Views
2K
Replies
4
Views
2K