Does the expansion of the universe also cause an increase in overall entropy?

[Chalnoth]

So if a system settles into its state of maximum entropy, wouldn't that dismiss the need for a big crunch?

I don't understand, why would there ever be a need for a big crunch?

 

[Entropee]

Well expansion speed does not exceed escape velocity, so wouldn't mutual gravitational attraction of matter cause it to contract at some point?
I read that somewhere, not sure if it's true.

 

[Chalnoth]

Well expansion speed does not exceed escape velocity, so wouldn't mutual gravitational attraction of matter cause it to contract at some point?
I read that somewhere, not sure if it's true.

This sort of idea leads to what is known as the "Jean's Length". Below the Jean's length, the typical speeds of particles are indeed lower than the escape velocity, and so stuff collapses, leading to things like galaxies, galaxy clusters, etc. Above the Jean's length, this isn't the case, and stuff continues to move apart.

Remember that due to the falloff of gravity, the escape velocity depends upon how far away from the center of mass you are.

 

[Entropee]

Oh that's a good point, so how would the escape velocity change as universe expands?

 

[Chalnoth]

Oh that's a good point, so how would the escape velocity change as universe expands?

Well, escape velocity is more a local effect. So it isn't really changed by the expansion. The expansion basically just sets the initial conditions.