expanding universe?

Question

the universe has been expanding since the big bang. but instead of expanding ast a slower rate, its going faster and faster. scientists think that its because of dark matter.

now if dark matter causes the universe to accelerate, how fast can it make it go. can it accelerate it to near the speed of light? and if thats the case, wouldnt the universe then be infinitely massive?

Answer 1

You are talking about dark energy, not dark matter. Dark matter come us when modelling the specifics of galaxy formation. Dark energy is more mysterious and contributes to the acceleration of the universal expansion.

Yes, the dark energy will eventually cause the expansionto grow until it is clse to the speed of light. At that point, our galaxy would be isolated and the rest of the galaxies would be outside of our visible universe. Talking about the mass of the universe is a rather tricky thing in any case. It is much easier to talk about the density. In a dark energy dominated universe, the density stays the same even as the expansion happens.

Answer 2

I think you've misunderstood the theory. Scientists believe the universe is still in it's expansion phase as a result of the momentum of the Big Bang.

One theory suggests that the mass of the universe will eventually cause the universe to slow down and contract under it's own gravity, ultimately resulting in the "Big Crunch". Another theory suggests that the universe will continue to expand and cool down. In any case, the motion of the universe will not reach light speed as it is already decelerating relative to it's initial velocity.

Answer 3

I'll bet there will be a lot of different answers to this one.

Anyway, I don't think it works that way. If you picture an object, say a galaxy, moving away from us at almost the speed of light, the light that it is sending back to us (the light that we are using to see this galaxy by) is red-shifted almost to the point of being non-existent to us. Imagine it faster and faster and when you reach light speed, this light is red-shifted to the point that it really is non-existent. (to us, once again. different frame of referrence and this light might well exist).

So if you imagine a universe expanding as fast as in your question, then the objects out there are undetectable to us.

Answer 4

No, actually, dark ENERGY is speeding the expansion of the universe, not dark matter. And no, there's got to be a point where the acceleration stops.

Answer 5

dark matter would be the determining factor in the contraction of the universe....not the expansion
dark matter, if it actually exists, would be the gravitational link between distant galaxies. But in order for them to contract there must be a certain amount of dark matter in the universe...and that my friend is the big question. How much of it exists if it actually does? Hope this helps