Thermodynamics

[sacscale]

Spacetime is flat for the visible universe; that is the part we can see. Objects so far away that their light has not reached us yet are part of the unobservable universe. What the spacetime curvature for the entire universe (observable plus unobservable) is unknown.

 

There is not a question of what the universe is expanding into. Per general relativity, the universe is expanding but it is not expanding into anything. There is nothing beyond the universe for it to expand into. Difficult to conprehend, I know, but this is the current understanding.

 

Not much more than the unobservable universe.

 

There is no center of the universe. It looks the same (on a grand scale) no matter where you are located in it.

 

Yes, everything is moving away from everything else but it all originated with the "big bang".

Edited March 21, 2011 by sacscale

[mooeypoo]

Please learn physics.

 

!

Moderator Note

Someone was nice enough to try and help you. Your reply was rude and unacceptable.

 

Please read our rules and etiquette. This attitude is unacceptable in our forum.

[sacscale]

!

Moderator Note

Someone was nice enough to try and help you. Your reply was rude and unacceptable.

 

Please read our rules and etiquette. This attitude is unacceptable in our forum.

 

 

There was nothing "nice" about the "help" in a forum on "physics". You seem to have an attitude.

[mooeypoo]

There was nothing "nice" about the "help" in a forum on "physics". You seem to have an attitude.

This is me being nice. So, let me rephrase:

!

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When you signed up to this forum, you agreed to our rules. You are disobeying these rules. We are kind enough to give you a bit of a heads up warning before we take action for violation of our rules.

 

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[swansont]

Why can't you view a coalescing cloud of matter as a collection of emerging centripetal concentrations. As they coalesce, their centers would be in motion relative to each other and they would be drawing matter away from their lagrangian point and thus creating an increasingly empty vacuum-space between them. The initial potential energy was in the dispersion of original matter. As the centripetal centers emerged, they would cause kinetic energy of the coalescing particles until a state of relative equilibrium was reached due to friction preventing further settling. How is this immune to Newtonian analysis?

 

How does a cloud coalesce if it doesn't shed energy?

[ajb]

If all you had was Newtonian gravity, you would trade kinetic energy for potential energy and back again. Masses wouldn't coalesce. You need other interactions for that.

 

 

How does a cloud coalesce if it doesn't shed energy?

 

This reminds me of a talk by a quack I went to a few years ago. The meeting was quite an open event on gravitational physics, unfortunately being quite open allows for some very distracting talks.

 

This guy showed us basic animations he had calculated based on just Newtonian gravity of how galaxies form. As he had no mechanism for the energy from each object to dissipate, for example I expect that gravitational waves would have been great for this, nothing coalesced and things just passed though each other.

 

I think he concluded that gravity cannot be responsible for the large scale structure we see. Or at least he was suggesting this.

 

It was pointed out to him that his simple model did not allow for any energy dissipation (either via terms based on fundamental physics or even just empirical) and that no-one was surprised by his results!

Edited March 21, 2011 by ajb

[lemur]

How does a cloud coalesce if it doesn't shed energy?

I said, "As the centripetal centers emerged, they would cause kinetic energy of the coalescing particles until a state of relative equilibrium was reached due to friction preventing further settling." I think I'm missing what you're arguing against that I said now. All I was trying to claim was that gravity can have an organizing/stratifying effect, i.e. anti-entropic. I guess you are pointing out that the kinetic energy generated as a cloud coalesces would result in radiation, which is entropic dissipation of energy from the system. I agree with that, but does that diminish the anti-entropic effect of the gravitational coalescing? Must entropy refer to net entropy of a system, or can one form of entropy be taking place while organizing forces are producing a new system of potential energies?

 

 

[swansont]

I said, "As the centripetal centers emerged, they would cause kinetic energy of the coalescing particles until a state of relative equilibrium was reached due to friction preventing further settling." I think I'm missing what you're arguing against that I said now. All I was trying to claim was that gravity can have an organizing/stratifying effect, i.e. anti-entropic. I guess you are pointing out that the kinetic energy generated as a cloud coalesces would result in radiation, which is entropic dissipation of energy from the system. I agree with that, but does that diminish the anti-entropic effect of the gravitational coalescing? Must entropy refer to net entropy of a system, or can one form of entropy be taking place while organizing forces are producing a new system of potential energies?

 

Ah, you used the "f" word. Friction. Which is not a gravitational force. Gravity is not causing the energy dissipation, which is increasing the entropy.