The Universe: Beyond

: In this model, if you travel in one direction long enough, you eventually end up back where you started . There is no "outside" because the fabric of space-time itself is all that exists.

: Our universe could be an isolated "island" floating in a higher-dimensional "super-universe". What's Beyond The Observable Universe? Beyond the universe

Some modern theories suggest our entire universe is just one "bubble" in a much larger sea. : In this model, if you travel in