Originally posted by apathist
I'd like to derail and ask why everything that exists wouldn't be included in the concept of 'universe'.
You can use that term in several ways. There are hypotheses floating about where our universe is a daughter universe of a parent universe where in that universe a black hole formed and we are the output of that black hole, what they call a white hole and our universe was squeezed out of the energy and mass of the parent universe black hole.
And the parent universe was the daughter of yet another parent universe, the grandparent of ours and so forth possibly ad infinitim.
So our universe and our time is only a local universe and our time is just local time, where our clock started some 14 billion years ago but there would be many other time frames in their own universe, some just starting compared to ours, others long dead or whatever happens to a universe at the wrong end of time.
There is some possible evidence, weak ATT, where they see these circular patterns in the CBR that should not be there according to modern physics.
They think those patterns were caused by another universe outside our framework banging into ours like two balloons bumping into one another.
And the physicists making that conjecture freely admit at this point in time it is just that, conjecture to try to explain some anomalous data in the background radiation charted back a few years.