The big crunch won't happen.
Thats right, won't. Not can't, won't. In order for the big crunch to occur, the big bang wall (a sphirical wall of dust and matter from the big bang) would have to decide to reverse it's infinite outward course and head back toward the center of the universe.
This can't happen because there is nothing outside the big bang wall to reverse it's course, and the center of the universe is not nearly big enough nor strong enough to have any sort of pull on the big bang wall.
Of course if there is a universe of matter there may be a universe of anti-matter somewhere else?

Your reasoning is flawed, and even those who know what they are talking about aren't really truly sure.

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Originally posted by tryptamine:
Your reasoning is flawed, and even those who know what they are talking about aren't really truly sure.

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I second that.

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Originally posted by SpaceFalcon2001:
This can't happen because there is nothing outside the big bang wall to reverse it's course, and the center of the universe is not nearly big enough nor strong enough to have any sort of pull on the big bang wall.

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The main flaw with that reasoning is assuming that the center of the universe is doing all the pulling. Every particle in the universe pulls at every other particle in the universe however slightly. Naturaly matter will pull together with any other matter available causing the formation of planets, stars, solar systems, galaxys, and globular clusters. But in turn these pull at each other too.

The only reason I can see for the universe not being able to colapse is because of the fact that during the big bang space itself traveled up to 4 times the speed of light away from the center of the universe. So space itself doesn't conform to the same rules as matter. However it does get warped around strong gravitational fields, so space itself could be sucked back in, throwing the whole debate up for grabs again.

Its not whats outside the universe that will afect its movment but what is inside that will, thats your main flaw.

CTR

is there not a theory that states that the matter in the universe is/will be spaced out enough to the point that gravity and whatever forces that would be pulling it together would not apply and the universe would just continually expand?

i know its a long scentence but i've had a long day.

I can only assume the energy dissipated in the big bang is finite. If it is, then the pulling of gravity, which is currently assumed to be of infinite duration, will eventually slow down the expansion of the universe and pull everything together at the center of mass, presumably the center. Sadly, I won't be around to see it. I'm sure it would make quite a show.

Now I'm drifting into Hitchhiker territory...

Oh, well.

The energy released would be finite (I think - a VERY large amount, but finite), but the second law of thermodynamics - entropy is increasing. So you're getting more free energy and less mass... could make the big crucnh impossible. And no matter how far apart two things are, there is still gravitational pull between them. And as we get larger atoms with fusion in supernovae, for example, things get denser and gravity increases. Makes life interesting and possibly counters the entropy problem raised above. I dont know - this is all my theories, could be way out. Oh well!

I know that all matter is pulling on its self, but if a big crunch were to occur, something would have to be pulling stuff to the center, otherwise if you pull in all directions, nothing is effected.
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And no one has anything to say about an anti-matter universe? I think that would be kool, imagine the lighting, the objects, how things would be oriented... should i start a new topic with that in mind? ok.