Well here we go,

Expansion of the universe during Big bang causes matter to move away from each other faster than light.

This is why we see:
An homogenous universe.
Matter travelling away from us faster and faster the further it is from us.
Redshift increasing with distance from us.

No reletivity laws are broken.

It is only a way of looking at the universe as a whole. We can not see over the visual horizon of our universe. Expansion at the big bang means that there is matter that is further away from us than the time light has had to travel to us.

Is this wrong thinking?

Paul 8-[

If it was traveling faster than light how could we see it? I have no idea, I am just asking because I dont know.

Actually, yes, I think it is wrong thinking. The mainstream view does not have matter streaming through space away from us (although that was the mainstream view several decades ago). For the most part, the redshift is not caused by distant objects moving through space. It's the space itself that is expanding, and this gives the appearance that the distant objects are moving away from us, which in a sense they are, but not because they are actually moving through space, but because the space between us and them is expanding. (This stretches the wavelength of the light traveling through it and causes the spectral lines to shift toward the red end of the spectrum.)

You're right - we cannot see beyond our light horizon, but that horizon is constantly expanding (at the speed of light). It seems the universe is much, much larger than the portion within our light horizon. Calculations indicate it is 10^23 times larger!

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It's interesting to note that if the acceleration of the expansion is a constant (or if it increases with time), then although the horizon moves away at the speed of light, distant galaxies will actually overtake it. Eventually, anything that isn't gravitationally bound to us will disappear over the horizon. Goodbye, distant galaxies!

So basiclly expansion causes redshift
Matter does not move through space faster than light. however due to expansion matter can be further away from us than light has to travel.

The size of the universe over our horizon has been esitimated as stated above. Does this esitmation put most matter over the horizon or within our horizon?

If it is over our horzizon I say without breaking any laws that most matter in the universe is moving away from us faster than light.

How does that statement sit? :^o

Just to be clear - do you mean constant acceleration now or constant acceleration since the Big Bang? My understanding of the current Big Bang Concordance model is that expansion would have slowed until z=~1-2 and then acceleration began.

... and if most of that matter was beyond the horizon, could it be "pulling" the Universe to cause the expansion?

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"Imagination will often carry us to worlds that never were. But without it we go nowhere." - Carl Sagan

I don't think it would matter, actually. As long as the acceleration doesn't go away in the future, we should lose things over the horizon. I doubt we could ever notice on human timescales, but it's just strange to me to think that there might be things that were once close enough for their light to reach us in the lifetime of the universe, but no longer are.

If the event horizon is fixed (in the sense that we can not see beyond it,) and, over time more mass/energy passes beyond the horizon. Is the Universe not lossing mass?

What I mean is, is not what directly influences us not what consists of our universe?

If mass/energy can not be detected, is it not, in effect, outside of our Universe?

I am probablly playing with semantics, but I am having a hard time seeing where I am in error.

As all matter in our universe has a different horizon the only guage that I can see as an appropriate measure of the size of our universe is:

The effect of gravity from matter both within and beyond our horizon is the forse that defines the size of our universe.

How about that?

In answer to the above
If the event horizon is fixed (in the sense that we can not see beyond it,) and, over time more mass/energy passes beyond the horizon. Is the Universe not lossing mass?
No the matter is still there and still exerts effects on our visiable universe.
Don't be confused with the visible universe and the total of all matter and space that makes our universe.

What I mean is, is not what directly influences us not what consists of our universe?
Matter beyond our horizon again effects matter inside our visible horizon.

If mass/energy can not be detected, is it not, in effect, outside of our Universe?
This matter can be detected and does affect our universe.

I hope this helps.
What I would like to know is how big is it?[/b][/i]

I think that snowcelt actually has it right here. Any matter that is beyond the visible horizon (assuming that the expansion of the universe is such that it will never again be within the horizon) can no longer have a causal effect on us. That means that although it could have an effect on objects we can see now, we'll never see the results of those changes.

No actually, it can't be detected by any means. Let's try to think about this for a moment. There's us, there's galaxy A, still within the visible universe, and there's galaxy B, which is beyond that horizon. The definition of the visible horizon is that it's the point at which a signal moving at light speed (as fast as it can go), will just make it to us in the lifetime of the universe. That's any signal, including a gravitational influence.

With the expansion accelerating, objects that are beyond the horizon will never be overtaken by the horizon, which means that any signals from them will never reach us in the future either. Though the signals may be travelling at the speed of light, the space between us and the source is expanding fast enough so that the signal will never actually get any closer to us.

So, galaxy B is still within galaxy A's horizon, and exerts some gravitational effect. For our purposes, we'll say that this is some weird effect that will cause a clearly visible change to galaxy A. That gravitational signal has to propagate at light speed from galaxy B to galaxy A, and then the light that lets us know the change has been made has to travel from galaxy A to us, also at light speed. But we just said that a signal travelling at light speed couldn't make it to us in the lifetime of the universe, and breaking up the trip into two separate segments doesn't help the signal get here faster.

Why won't we see it? Well, remember that we don't see galaxy A as it is now, but rather as it was a long time ago, and that signal from B to A will take time before it gets there. Galaxy A moves further away from us during that time. By the time the signal has travelled from galaxy B to galaxy A, galaxy A will have slipped beyond the horizon, too, so although it is affected by galaxy B, we'll never see the change. It has to be far enough away for this has to be the case, or else a direct signal from galaxy B to us would be able to make it, too, and galaxy B wouldn't have been beyond the horizon in the first place.

That means that snowcelt is right; one of the effects of an accelerating expansion is that matter will leak out of the visible universe at the horizon. :-?