Originally Posted by JustAsking

David,

The question used to be answered by looking at the total mass of the universe and the velocity of deep space objects. Knowing those things, you can determine whether things are moving at below or above escape velocity. If they are above escape velocity, then the universe would expand forever. If they are below escape velocity, they will eventually slow down to a stop and then fall back towards the center of mass of the universe.


But since that time (the 1970s), there is more evidence that the universe is far more massive than what you get when you add up all the apparent observable mass. The extra unassigned mass is attributed to something called Dark Matter. It is a hot topic in astrophysics right now.

I think at the moment, the question is unanswerable. Your working premise that the chain of causation is infinite and matter can't be created or destroyed is interesting, but I don't think that accounts for "leaks" of energy into or out of the universe. I would have to say that your premise can only be speculative. But it is surely an interesting question.