The universe has no "up"

Some potentially previous ones, yes. But universes, like stars, may have different fates depending on their mass-energy and composition (which for a universe means the values of its fundamental constants established as its symmetry breaks). Just as some stars will collapse into a black hole, some possible universes will end in a Big Crunch, and in fact that was the favored theory for our own universe’s fate as recently as twenty years ago before astronomers obtained better measurements showing the expansion would defeat gravity. So while our universe is (probably) destined to end in a Big Rip, and thus subsequent Big Bangs, if any, born from it’s corpse would come from that, we don’t yet know of any way to study which of the possible preconditions, if any, gave rise to our own Big Bang.

1 Like