An advanced species that does not have FTL travel methods lives in a universe with the same fundamental laws as our own. The species can either create, or know when and where a new universe inflation will take place. If we compare it to what we know about our universe’s early stages, is it possible that an outside life form could get into the newly expanding universe?

As both universes will be expanding and the force of the birth of the new universe could mean nothing could be within a certain distance at its start, is there a specific time or way to approach the new universe so that an outside life-form can enter it or will the expanding space make it forever out of reach?

Edit: The new universes will appear in the species universe and expand into it. They will have the same properties as the original universe, the issues I am wondering about are, will the Big Bang send gravitational waves that will send the original universe away? if not, will the steadily expanding universe expand too far for a civilization to stay at a safe range from the initial bang
but close enough to be able to reach it after it has cooled down?

Edit 2: Surviving in the new universe isn't an issue and there is no boundary to break, as long as it isn't still a hot plasma soup existing in its space, it will be no different to what they are used to.

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    $\begingroup$ Just to clarify, your starting premise is that a new "big bang" will happen within our universe, generating a new wave of matter prior to the heat-death of the universe, sort-of "renewing" our universe with fresh matter and energy. You want to know if a species of non-superbeings could set themselves up to migrate into this "new" big bang and colonize it without being destroyed somehow. $\endgroup$
    – DWKraus
    Jun 1, 2020 at 21:24
  • $\begingroup$ @DWKraus exactly! Not destroyed or unable to reach because of expansion and speed limits of travel. $\endgroup$
    – user69935
    Jun 1, 2020 at 21:28

1 Answer 1


Probably Not

Nothing in our current understanding of cosmology allows for matter from one universe to move to another.

Moreover, "when" and "where" are not concepts that exist in the context of extrauniversal "space". Space and time are constrained by the boundaries of our universe. "Outside" does not have a meaningful definition, because the "direction" to that universe cannot be expressed in terms related to our own universe. So even assuming you could get "outside" our universe without faster-than-light travel (there is no known way this could happen), there is then no way to express which "direction" you'd go to find the new one, because there is no space.

Even cause and effect don't hold sway outside of our universe, so it's likely impossible to "detect" a "new" universe inflation, because its temporal dimension(s) are completely unrelated to our own.

The only mechanism that offers some possibilities is string theory which is waaay beyond my pay grade, but which has been mined by science fiction authors as a means of connecting universes (Marvel did it most recently, but Crichton did it as well). It postulates that you might be able to visit other universes in the multiverse by travelling along one of potentially many other dimensions that are curled up in spaces smaller than the Planck Length. How one goes about translating along such a dimension is where the handwavium comes in, because, to put it simply, we don't know, and we don't even know if those dimensions are there.

So with the reality check tag in place, my answer at the top stands - there's almost certainly no way to travel to a different universe; and even if there were, its inflation state is orthogonal to our own temporal dimension, so if you have a travel mechanism, you can likely arrive anywhen in the target universe. (Which violates causality in that universe, of course, but that may or may not be a problem.)

Edit in light of new information in comments and edit to the OP:

As indicated in the comments, nothing we know about cosmology suggests that a new universe could appear within an existing universe. Among other things, for a universe to begin inside our universe would violate the law of conservation of mass/energy. The singularity preceding the new Big Bang would require a universe's worth of matter and energy. Our universe's creation does not violate that law, because the law only holds sway within the boundaries of our universe.

The closest we might ever see is False vacuum collapse - a different set of laws expanding from a nucleation point at the speed of light. This could be harmless or intensely destructive, but in either case, inescapable.

Moreover, without FTL, not only is it impossible for your hypothetical species to outrun that boundary, they are not likely to be able to explore much of it (or the existing universe), assuming they survive the transition.

Edited in response to the second edit:

Notwithstanding my preceding stuff re: a new universe not forming within the confines of an existing universe, assuming that this new universe follows the pattern of our own, it'll only get down to the balmy temperature of 4000 K (3727 C) after about four hundred thousand years. So it would be a bubble eight hundred thousand lightyears across. Without FTL, that is an inconceivably huge bubble, which is still expanding outwards at the speed of light. And you'd only be seeing the first atoms being formed "inside" it.

So, still no.

  • $\begingroup$ The new universe isn't outside, sorry if I didn't make that clear, its within our own universe and it will expand into ours. $\endgroup$
    – user69935
    Jun 1, 2020 at 20:31
  • $\begingroup$ Ah. @RandySavage - universes don't form within existing universes, again, as far as our understanding of cosmology is concerned. We can state fairly definitively that it hasn't happened within Earth's light cone, because there are all sorts of signs that would demonstrate it happening. $\endgroup$
    – jdunlop
    Jun 1, 2020 at 20:59
  • $\begingroup$ Its something I have wondered for a while, if a universe was born within another, even if this is late in a universes predicted life and its extremely expanded, if an advanced species could get into a new big bang thats fairly early, as in first few billion years, so they can reach as many points in the new universe as possible before that expands too far. $\endgroup$
    – user69935
    Jun 1, 2020 at 21:10
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    $\begingroup$ @RandySavage - edited to match comments and changes to the original question. Without FTL, they won't be able to control how quickly they enter any barrier moving at the the speed of light, nor would they be able to "reach as many points as possible". $\endgroup$
    – jdunlop
    Jun 1, 2020 at 22:49
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    $\begingroup$ @RandySavage - edited once again to address your own edit. $\endgroup$
    – jdunlop
    Jun 2, 2020 at 0:10

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