Is There a Maximum Limit to Entropy Increase in an Expanding Universe?

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Discussion Overview

The discussion revolves around the concept of entropy in the context of an expanding universe, specifically questioning whether there is a maximum limit to entropy increase and the implications of reaching such a limit on the ability to do work. The scope includes theoretical considerations and interpretations of thermodynamic principles.

Discussion Character

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

Main Points Raised

  • Some participants reference the 2nd law of thermodynamics, which states that entropy can only stay the same or increase over time, raising the question of a potential maximum limit to this increase.
  • One participant mentions the concept of heat death of the universe, where maximum entropy is reached, leading to a state where energy is no longer available for work.
  • Another participant suggests that maximum entropy is defined as a state where no macroscopic changes can be observed from microscopic alterations.
  • Concerns are raised about the rapid increase of maximum entropy in relation to the universe's expansion, questioning the mechanisms behind this phenomenon.
  • A participant expresses confusion regarding how the first law of thermodynamics aligns with the idea of increasing maximum entropy, indicating a potential gap in understanding related to thermodynamics and cosmic expansion.

Areas of Agreement / Disagreement

Participants express varying interpretations of entropy and its implications in an expanding universe, with no consensus reached on the existence of a maximum limit or the relationship between entropy increase and the universe's expansion.

Contextual Notes

Some discussions involve assumptions about thermodynamic principles and the definitions of entropy, which may not be universally agreed upon. The relationship between entropy increase and cosmic expansion remains unresolved.

zeromodz
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The 2nd law of thermodynamics states that entropy can only stay the same or increase given time. My question is, is there a max limit to how much entropy can increase? And when it reaches this limit, can energy do any work at all?
 
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Kelvin came up with this idea of heat death of the universe. That is where entropy reaches its maximum state, all matter is maximally disorganized, and energy is no longer available for doing work. Kind of a grim thought.
en.wikipedia.org/wiki/Heat_death

In an isolated system there is what's known as thermodynamic equilibrium. Once an isolated system reaches this state, it will cease to change.
en.wikipedia.org/wiki/Thermodynamic_equilibrium
 
I think the heat death link is good.

You've reached maximum entropy whenever you can't get a different macroscopic reading from microscopic changes.

As a side note, most people are only familiar with the defenition of entropy from thermodynamics. Understanding it from a statistical mechanics point of view added a tremendous amount of meaning to the topic for me. YMMV.
 
It says on wikipedia that the maximum entropy in the universe will rapidly increase far faster than entropy in general increasing, pushing us away from "heat death". Why is it that the maximum entropy increases so fast because of the expansion of the universe?
 


1)example for function A and B such that function f and composite functions of g o f are both injective but g is not injective

2)1)example for function A and B such that function f and composite functions of g o f are both surjective but f is not surjective?
 
zeromodz said:
It says on wikipedia that the maximum entropy in the universe will rapidly increase far faster than entropy in general increasing, pushing us away from "heat death". Why is it that the maximum entropy increases so fast because of the expansion of the universe?

I find it very difficult to understand how this could be the case since the first law seems to indicate that no more energy is being added to the universe. (My lack of understanding might be due to my ignorance of thermodynamics or the theories behind the expansion of the universe. Take you pick :biggrin:)

An increase in volume (without a change in pressure or temperature) is an increase in entropy. If the universe is expanding rapidly, it stands to reason that entropy is as well. Clearly there is something I'm missing.

I wanted to check the source for that statement, but Wikipedia doesn't cite one!
 

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