Hawking said that universes are like bubbles that pop into existence and pop back into the vacuum some form then immediately pop, he calls this space-time foam, our bubble doesn't seem to pop immediately after it's formed, is there a reason for our bubble staying so long, is it because we're simply too tiny to notice?

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    $\begingroup$ Hi! It would be very helpful if you could provide for us a citation of where Hawking said this. $\endgroup$ Jul 29 at 23:14
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    $\begingroup$ If you're talking about QUantum foam that is not universes poping into existence, but the quantum fluctuation of spacetime on very small scales. So I think we really need that citation for Hawking, to see what he really said. $\endgroup$
    – James K
    Jul 30 at 11:00
  • $\begingroup$ What is Hawking's spacetime? $\endgroup$ Jul 30 at 15:53
  • $\begingroup$ I saw it on the yt video, might not be reliable I think, that you are all so unfamiliar with it. $\endgroup$
    – Lawyer
    Jul 30 at 18:03
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    $\begingroup$ What is the video called? I only know Hawking's spacetime is one with a complex time. Imaginary time to account for the beginning of time. The rest is just a curve spactime evolving to present day universe. It could be that this universe is a volume in an inflating universe. Its not co-inflating so to speak. It stopped co-inflating after matter was formed. In other parts of the infinite space smaller or larger bubbles can be found. As I explained in the answer. I dony believe in it. $\endgroup$ Jul 30 at 18:49

I think you refer to the theory of eternal inflation. Space is infinite in that model and eternally inflating for some magic reason.

For some magical reason, at some places inflation comes to a halt and a universe comes into being. It seems as local bubbles appear in which inflation is much less than in the rapid expanding surroundings.

For some magical reason in all these bubble pockets the laws of physics and amount of matter can vary. So this can give rise to different kinds of bubble universes. Some last like ours, and will be taken up in the bigger picture of the externally inflating space (presumably like ours in the far future. Some will live shortly and are almost immediately "taken up" again in the whole. Only to have added a tiny amount of matter.

Note that this is a bit similar to the pyrotechnical universe but that's another road to travel.


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