Is the entropy in the universe increasing?

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Discussion Overview

The discussion centers around the question of whether entropy in the universe is increasing, exploring the implications of the second law of thermodynamics and the conditions under which entropy may change. Participants examine theoretical and conceptual aspects of entropy, including its behavior in isolated systems and scenarios involving local decreases in entropy.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant asserts that entropy is always increasing with every interaction of energy in the universe, suggesting that it can only stay the same or increase, but never decrease.
  • Another participant introduces caveats to the second law of thermodynamics, stating that entropy increases for isolated systems that are far from thermal equilibrium, and it remains constant at thermal equilibrium.
  • A different viewpoint discusses the example of a hard drive, where local entropy can decrease due to the organization of files, but emphasizes that this does not contradict the overall increase of entropy in the universe due to energy consumption and heat generation.

Areas of Agreement / Disagreement

Participants express differing views on the conditions under which entropy may remain constant or decrease locally, indicating that multiple competing views remain without a consensus on the overall behavior of entropy in the universe.

Contextual Notes

Participants mention specific conditions related to the second law of thermodynamics, such as isolation and thermal equilibrium, which may influence the discussion but are not universally agreed upon. The implications of local decreases in entropy versus the overall increase in the universe's entropy are also highlighted as a point of contention.

harvhk852
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I have been stuck on the question for so long...please can you see if you can help me out.:smile:

Is the entropy in the universe increasing? If yes, when did entropy start increasing? if no, what is happening to entropy in the universe?

Thank you very much for any help.
 
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Entropy is always increasing with every interaction of energy in the universe. Entropy can either stay the same or it can increase. It can not decrease*.

*Caveat: One form of the second law states that entropy can not be destroyed, but this is truly not a law. The probability of entropy decreasing is so small that it would take a very, very long time for it to ever happen. In other words, it is very safe to say that it will not decrease.
 
Hi Fred,
FredGarvin said:
Entropy is always increasing with every interaction of energy in the universe. Entropy can either stay the same or it can increase. It can not decrease*.

*Caveat: One form of the second law states that entropy can not be destroyed, but this is truly not a law. The probability of entropy decreasing is so small that it would take a very, very long time for it to ever happen. In other words, it is very safe to say that it will not decrease.

Correct me if I am wrong here, but I think there might be two more caveats (actually, boundary conditions) that might need to be added to quote the second law in its complete form:

Entropy increases for a system that is:

a) Isolated and
b) Far from thermal equilibrium.

I believe that when a system is at thermal equilibrium (and isolated) is the case you cited about entropy remaining constant. The reason I bring up condition (a) is because some folks can get confused by a control volume where local entropy decreases do occur (as a result of energy being added to the control volume).

Am I off base here? :biggrin:
Rainman
 
I always remember talking about this in intro college physics with the example of a hard drive -- in a sense, the surface of the hard drive is decreasing in entropy (because the files have some "order" to them). However, the entropy of the universe is increased because of the fossil fuel being burned to generate the electricity -- the heat from the processor, etc. So local entropy can decrease, but the entropy of the universe increases as a result.
 

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