The multiverse is a hypothetical group of multiple universes. Together, these universes comprise everything that exists: the entirety of space, time, matter, energy, information, and the physical laws and constants that describe them. The different universes within the multiverse are called parallel universes, other universes, alternate universes, or many worlds.
The multiverse or space as a whole is stretching and will continue doing so forever, but some regions of space stop stretching and form distinct bubbles. (Such bubbles are) embryonic level I multiverses.
…interpretations of quantum mechanics. In brief, one aspect of quantum mechanics is that certain observations cannot be predicted absolutely.
The ultimate mathematical universe hypothesis is Tegmark’s own hypothesis. This level considers all universes to be equally real which can be described by different mathematical structures.
