Roelof Wesselius said:
But if that is true won't there at the edge of that old universe be the remnants of another even older one?
I imagine it would depend on how this "cyclical expansion" operates. But in theory, there could be.
I've not read up on the current state of these new theories; including the latest iteration of the Big Bounce theory; but it would stand to reason that there could be an innumerable number of universes stacked on top of each other, expanding outward to some unknown
(or unknowable) fate. In fact, for all we know, this "stacking effect" could be a catalyst for the creation of other, newer universes.
Or, perhaps the expansion of a new universe simply "annihilates" the space-time of the older universe. Or maybe it assimilates the old universe, repurposing the old universes energy/mass.
Again, I can't say. And, for all intents and purposes, neither can modern physics. But at least we're still looking for answers.
(and finding more and more each day)