OT - Physics Question on Anti-Matter

[Raapys]

Assuming that there were no unknown factors( which there most certainly is ), wouldn't gravity keep the universe from maximum entropy? Is there anything to indicate the universe wont just do the whole big-bang thing over and over again?

I also thought I read somewhere that they'd discovered that light didn't actually travel infinitely, but somehow bended back towards us when it had travelled for some time?

[Phoenix-D]

That's one possibility, but as of the moment the Universe's expansion actually seems to be speeding up, not slowing down..

[aegisx]

Last i heard it was speeding up too. Really, the 'Last Answer' story answers this well

So if everything we know now is true 9which is probably isn't), the universe will run out of 'energy' some day.

[Raapys]

Yeah, but when that 'energy' is depleted and everything has 'stopped', gravity will still be there( as far as we know ). What is to stop it from pulling everything together again?

I read the Last Answer. It was a nice read, thanks.

[aegisx]

Gravity would dissipate to pretty much nothing I suspect. Gravity is a force and spread over theoretical particles called gravitons. So as stars, planets, elements, atoms and particles break down, so does the gravitational force. All these things are held together by very strong forces compared to gravity, so if those are breaking, gravity probably isn't a big issue.

Of course, this is just based on my basic understanding and I could be wrong.

[Raapys]

Well, I wont claim to know any better, but I would have thought that if gravity was still there, however 'weak', the particles would slowly start to pull together again; unless something was actually exerting force on them( stronger than the gravity ), keeping them apart.

Anyway, if indeed the expansion is speeding up, that means energy is being continusly applied to the mass in the universe( thus providing the speed increase). Since energy = mass ( right? ), that means further that the amount of mass in the universe is increasing as well? And since all mass has gravity, as far as we know, that also means gravity increases? Thus eventually becoming strong enough to counter whatever other force is pulling the stuff apart...?

My non-existing education got cut short, so I'm a little out of the loop. Please correct me if something's wrong with my understanding.

Also, wont the whole 'expansion speeding up' thing also mean the entire mass of the universe will be traveling at light-speed in a 'few years'?

[Suicide Junkie]

Its not the objects accelerating (IE Kinetic energy), but the underlying spacetime itself expanding.

BTW, if something is at escape velocity, it will never fall back (barring interference from other space objects)... that's because even though gravity is always there tugging on it, gravity is weakening faster than the speed is decreasing.
On a parabolic "orbit", the speed approaches zero as time approaches infinity... but it never quite manages to go negative and loop back. No matter how long you wait, you've always got just a little speed left, and gravity is *just* slightly too weak to stop you.

[PvK]

Well if you want infinite money, just become a bank and start charging compound interest...