I have wondered whether the Universe kind of breaths in an out. That the universe is expanding due to the initial energy of the big bang and that as the momentum of the expansion begins to decline and gravity takes over that it begins to retract back into a singularity until we get another big bang. I dont know whether astronomers have worked out if the universe will keep on expanding but I believe the sums depend on the amount of dark matter that is estimated be in existance. If the universe is expanding and contracting this would explain to some extent a kind of beginning although I would assume that this process would have to be infinite too.
