- There is a cosmological model, called Black-hole cosmology, in which the observable universe is the interior of a black hole existing as one of possibly many universes inside a larger universe.
- Energy probably gets sucked into black holes, and some energy from its other universe gets ejected into ours. It's been converted to gamma radiation, almost pure energy. Like a line of different universes then. A stream of them, and more abd moee of the energy in a universe leaks into the next one as it gets older as everything becomes black holes or is sucked into them. I guess a little energy is lost in each one. Maybe it's sucked back up again in the big crunch, like a drop of water being sucked back up Into a bottle. All the energy just leaks through and becomes empty except for the remnants of gamma ratiotion from all the black holes zooming all over the place. Maybe this happens because both universes are already "full" and they have to squirt the same up as what goes into them.
- Lee Smolin apparently writes about this idea.