SexySam182 Wrote:
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> Is reversal the thing where the universe is
> actually expanding now at a greater rate than
> ever? And no-one knows why.
>
> I'm absolutely fascinated by this, its just a
> shame A-level physics barely touches on the
> subject, but I would guess its because much in
> space cant be scientific fact as we arent sure
> what happens. But it would be a hell of a lot more
> interesting than resultant forces.
Pretty much, before scientists "discovered" (more like stumbled across) dark matter there were two theories as to what would happen to the universe: either the mass density of the universe was greater than the critical mass, at which point the universe would collapse having reached a "maximum" size, ending in the same way the universe started, or if the density were below the critical mass the universe would continually expand, slowing down over time but not stopping.
However, now we know that dark matter exists nobody is quite sure what will happen. There are several potential outcomes, perhaps the universe will continue to accelerate until the universe essentially tears itself apart, heat death and several other theories.
It is entirely possible (as I said before) that while the universe expands it could contract again. This does seem unlikely given that dark matter exists in the universe but to be fair when you don't really know what's going to happen any theory could hold
Does seem most likely that the universe will continue to accelerate, given this condition it seems that heat death would be the most likely. As the universe expands everything else has to as well. The space in between galaxies stretches cooling the universe down so eventually everything just destroys itself.