expanding universe - entropy by default

[DRZion]

The expanding universe is by default increasing in entropy. Shouldn't then most reactions be expansive by default? These, by definition, increase entropy.

If the majority of reactions were entropy-reversed then the universe would start contracting. However, since the majority of reactions are entropy-increasing the universe expands, or maybe because the universe expands they are entropy-increasing.

The second law is empirical - it is in fact possible for entropy to reverse for short periods of time. However, if this were the dominant form of reactions our universe would contract, imo.

 

[DRZion]

If there was any region in the universe where entropy was reversed, it would be thermodynamically favorable for matter to converge rather than disperse, and these areas would tend to get smaller as the universe gets bigger. In other words we would never observe these areas because they would get smaller while the universe would get larger.

 

[quantum_wave]

The expanding universe is by default increasing in entropy. Shouldn't then most reactions be expansive by default? These, by definition, increase entropy.

If the majority of reactions were entropy-reversed then the universe would start contracting. However, since the majority of reactions are entropy-increasing the universe expands, or maybe because the universe expands they are entropy-increasing.

The second law is empirical - it is in fact possible for entropy to reverse for short periods of time. However, if this were the dominant form of reactions our universe would contract, imo.

For clarification, I take it you are talking about the universe of BBT, i.e. one that had a beginning circa 14 billion years ago? Clearly entropy of that universe is increasing and will increase in total until something akin to the Big Rip occurs. In that universe there are patches of reverse entropy all over the place but the indication is that there is acceleration of the expansion which rules out a period of reverse entropy on a grand scale.

 

[Pincho Paxton]

I don't think that accelerating expansion is a form of entropy. If anything, it's the opposite to entropy. It's growth. I think that entropy is localised anyway, it's a form of buffer, and caused by reducing waves through substance. But even reducing waves through substance is expansion. Most forms of energy lead to expansion, it's hard for a wave to pull itself back to where it came from.

 

[DRZion]

I don't think that accelerating expansion is a form of entropy. If anything, it's the opposite to entropy. It's growth. I think that entropy is localised anyway, it's a form of buffer, and caused by reducing waves through substance. But even reducing waves through substance is expansion. Most forms of energy lead to expansion, it's hard for a wave to pull itself back to where it came from.

I say growth is entropy. If you have particles localized on one side of a partition and then you open that partition you will get an increase in entropy as the particles diffuse

The point is that our definition of entropy fits all too well with the concept of an expanding universe. Perhaps chemistry evolved during the milliseconds right after the big bang to accommodate this expansion - and this is why entropy increasing processes dominate the universe.

So there are pockets in our universe where entropy is decreasing? Do you mean black holes?