I have made up a theory of my own to explain the origins of the universe via a “multiverse” connection thingy. In a nutshell there are many universes, each linked by black holes and “space pores” which are miniature white holes all over our universe that spurt out matter from other universes.
Since anything and everything could get pulled into a black hole i thought what if those black holes led to other universes? It would make sense because that’s why some universes are expanding and others contracting.
The matter that uses these wormholes might not emerge on the other side the same. They might be turned into some other form of matter/energy. like perhaps all the “matter” coming in from other universes might be being turned into “dark energy” filling up our universe causing it to expand.
and you might wonder “But where does it all come out??” to that I must say i have not thought of anything besides “space pores” to explain where it gets ejected out from.
Or maybe… just maybe… cats are these mysterious suppliers of mass and energy (see variable density of cats)