There seem to be 2 different definitions of the term "multiverse".
One of them is in the quantum sense: the same region of space contains multiple (perhaps infinitely many) universes at the same time, until it's "measured", at which point it randomly selects one of those universes which then gets patched back into the surrounding universe in a consistent manner.
The other definition is the (perhaps infinite) set of universes that exist as bubbles in some number of dimensions which is at least 3 but possibly more, whose coordinates do not overlap anywhere. This is the more cosmological meaning of the term. Some of these "universe bubbles" are moving apart faster than the speed of light.
In the latter case, we may never know the truth because we may never be able to receive any information from, let alone exchange any information with, any of them. And the former case might be an elaborate statistical deception, which would have profoundly negative consequences for the prospect of quantum computing. To help explore this question, I've posted a video.
One of them is in the quantum sense: the same region of space contains multiple (perhaps infinitely many) universes at the same time, until it's "measured", at which point it randomly selects one of those universes which then gets patched back into the surrounding universe in a consistent manner.
The other definition is the (perhaps infinite) set of universes that exist as bubbles in some number of dimensions which is at least 3 but possibly more, whose coordinates do not overlap anywhere. This is the more cosmological meaning of the term. Some of these "universe bubbles" are moving apart faster than the speed of light.
In the latter case, we may never know the truth because we may never be able to receive any information from, let alone exchange any information with, any of them. And the former case might be an elaborate statistical deception, which would have profoundly negative consequences for the prospect of quantum computing. To help explore this question, I've posted a video.
