What might exist outside the observable universe? Then, what could be beyond that?
Possibilities are endless. But here are some likely scenarios:
- There could be much more space like the space we can observe including more galaxies, gas clouds, stars and planets. The universe could be substantially larger than we observe.
- If you were able to travel beyond the observable universe, it is possible you would simple travel back into the universe you came from, just like light gets curved back into a black hole.
- There could be a barrier/edge beyond which a completely different type of “space” existed with different physics.
- There could be many universes, perhaps one for every quantum possibility in our universe.
- A “foam” of universes could exist with each bubble in the foam representing a different universe.
Nobody knows, yet. For the former, we haven’t been able to observe it so far and for the latter, we might never be able to observ
We can’t observe beyond the boundaries of the observable universe because the light from beyond hasn’t had the time to reach us yet, in the 13.8 billion years since they first emitted light.
Beyond this? Nobody knows. The universe could potentially be infinite and have no boundary or it could end shortly after this observable region. Some physicists have estimated the size of the universe to be somewhere in the range of 200–250 billion light years. But we simply don’t know. Other scientists suggest that our universe is just one of an infinite number of multiverses. We couldn’t possibly comprehend or hypothesize what could be beyond a possible boundary of the universe because it’s literally beyond what we understand of our physical world and the dimensions in which it exists (which it’sall pretty complex on its own). all
In addition, at constant expansion rates we may reach a point in the future where no more light from farther away objects will reach us ever again, as the expansion rate of even the closest galaxies to us accelerates past the speed of light.
Not by the “obvious” method of travelling faster and faster.
All hypothetical techniques of travelling, in human terms, faster than light involve some sort of “trickery” such as wormholes, hyperspace, or distorted spacetime. All of which are currently entirely in the realm of fantasy.