I'm no astrophycicist - not even sure I spelled that right - but I once read that as stars reach the end of their lifecycles and become black holes, they swallow all else matter in the universe, which is sort of predictable. You would think that might happen. However, this article also claimed that even the super-black holes of the distant future can't contain all their mass/energy and that minute stray particles will escape it. Over trillions and trillions of years, this radiation would escape into the true nothing and loosely form atoms greater than the size of the current universe (don't ask me), but these too would eventually disintegrate or disperse and the universe would eventually be a featureless, infinite void ..
My father believes that after something like this, events that lead to big bang(s) will recur. Perhaps he's right? Noone knows
