Max Entropy: Second Law of Thermodynamics & Its Effects

  • Context: Graduate 
  • Thread starter Thread starter kky
  • Start date Start date
  • Tags Tags
    Entropy Maximum
Click For Summary

Discussion Overview

The discussion centers around the implications of the Second Law of Thermodynamics, particularly in relation to the concept of entropy and its maximum in the universe. Participants explore theoretical aspects of entropy increase, the conditions under which it occurs, and the potential state of the universe at maximum entropy.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant states that the entropy of the universe always increases, suggesting that it tends towards a maximum, and questions whether this maximum can be calculated.
  • Another participant agrees that the universe will reach a maximum entropy but notes the difficulty in predicting when this will occur, describing the state of the universe at maximum entropy as "heat death."
  • A third participant expresses a personal emotional response to the concept of heat death, indicating a sense of hopelessness associated with it.
  • A later reply challenges the straightforward application of the entropy formula to the universe, arguing that the absence of an external heat source complicates the situation and emphasizing the nature of entropy increase in closed systems.
  • This reply also suggests that at maximum entropy, mass would be evenly distributed and temperature uniform, but notes that the approach to this state is asymptotic due to the nature of entropy gradients.

Areas of Agreement / Disagreement

Participants generally agree that the universe will reach a maximum entropy, but there is disagreement regarding the implications of this state and the feasibility of calculating when it will occur. The emotional responses to the concept of heat death also indicate differing perspectives on the topic.

Contextual Notes

There are limitations in the discussion regarding the assumptions made about the universe as a closed system and the implications of external heat sources. The mathematical steps involved in calculating maximum entropy remain unresolved.

kky
Messages
7
Reaction score
0
By the second Law of Thermodynamics, we know the Entropy of the Universe always increases.
But we also know by the formula dS = d'Q/T that when we supply heat and increase the Entropy we also increase temperature. As for a given amount of heat the increase in entropy is smaller at a higher temperature than at a lower temperature, it follows that though Entropy always increases, it becomes harder to increase the Entropy the more we increase it. Extending this argument to the Universe, is it correct to say that the Entropy of the Universe tends off to a maximum?
If so is it possible to calculate this maximum with respect to any reference? And what would the Universe be like when we reach this maximum?
 
Science news on Phys.org
Yes... the Universe is going to reach a maximum of entropy, but guess when it will happen it's quite an impossible task. However it is known how the universe will look like at its maximum of entropy: it will be dead!
This death is called "Heat death" and you can refer to this "site"[/URL] for more details
 
Last edited by a moderator:
I just hate thinking about heat death... It takes away hope...
 
kky said:
But we also know by the formula dS = d'Q/T that when we supply heat and increase the Entropy we also increase temperature. ... Extending this argument to the Universe, is it correct to say that the Entropy of the Universe tends off to a maximum?

It's difficult to extend this equation to the universe, since there isn't an external heat source. Instead, we should consider how entropy increases in a closed system. Spontaneous processes tend to smooth out gradients in mass, momentum, charge, temperature, and so on. At the inevitable point of maximum entropy, mass is evenly distributed throughout the cosmos and the temperature is uniform. But you are correct that we can only approach this point asymptotically, since the driving force to eliminate gradients is itself proportional to the magnitude of the unevenness.
 

Similar threads

  • · Replies 13 ·
Replies
13
Views
4K
  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 17 ·
Replies
17
Views
3K
  • · Replies 17 ·
Replies
17
Views
3K
  • · Replies 15 ·
Replies
15
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 16 ·
Replies
16
Views
2K