: 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.
If the universe is finite, it doesn't necessarily have a "wall." Instead, it might be curved like the surface of a sphere. Beyond the universe
: A common misconception is that the universe expands into something. In reality, space itself is stretching ; it doesn't need "empty room" to grow into. 3. The Multiverse and "Super" Universes : In this model, if you travel in