# Does entropy stop applying at a certain scale or only with certain forces?

Asked by

Zyx (

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November 15th, 2010

Sort of a followup question to an earlier one, where I learned that entropy doesn’t diminish heat. So clearly the sticky forces don’t diminish either… Is there anything else I should know? Is this part of why quantum mechanics tend to be harder to understand?

(Also: did I formulate my question correctly?(Specifically the “applying” part.))

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## 7 Answers

*“Is there anything else I should know?”*

We all have more to learn.

As I understand it, entropy is purely a statistical phenomenon and has no direct relationship with physics. It will apply as well at small scale as it does at large scale.

Your question seems well formed to me.

Entropy only really applies to fully isolated systems. If a system is not fully isolated, external forces will constantly push it away from entropy. That said, as best we know the entire Universe is a fully isolated system, and so it should eventually reach a state of absolute entropy. However, there could be forces that will prevent the Universe from ever reaching that state. I do not believe we understand enough about the shape and dimensionality of space-time yet to predict what state its accelerating expansion will eventually take it to.

@ETpro So would you agree heat implies >0 extra dimension(s)? Or is that just ridiculous? There’s probably a lot of research into this I don’t understand yet but if heat is a warped spacial dimension shouldn’t there be a pot of gold at the end of the rainbow?

@Zyx I am unfamiliar with any theiry suggesting that heat is a dimension. Sorry, can’t be of any help there.

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