Originally posted by Da Joker
So, can someone explain what Digi said in the post quoted above? Sorry, but I still don't understand a lot of things about this kind of stuff.
Its based off of old ideas about the end of the universe.
Basically, in the theory, gravity and the expansion of the universe are opposites. If one is stronger than the other, it will be the cause of the end of the universe.
If gravity wins, the universe will eventually slow its expansion, stop, and begin to shrink in on its own gravity. Some people posit that this will lead to another big bang. I don't understand how, but it is astrophysics, something that humans have a long history of being 100% correct about.
If the expansion is stronger than gravity, the universe will eventually expand so fast that it overcomes gravity, and eventually the atomic bonds holding matter together and will become some ever expanding mess of diffuse quarks.
If there are equal, the universe will maintain steady growth.
There are different ways of measuring both the mass of objects in space (which would cause gravity) and universal expansion. They find estimates for both values and put it in an equation of X/Y. X is expansion, Y is gravity. So far, the number is well greater than one, meaning that the expansion appears to be winning.
However, the "dark" matter and energy complicate things, as does the fact that we are humans.
He also added the proviso that this is all subject to change as we get better data.