Oh thats a tricky one Niamh! And the answer is, well we don’t really know! Because we live inside the universe, we can’t see whats beyond it, or even whats at the edges of it. Parts of it are expanding so fast, we may never see them, as they might travel faster than the speed of light.
Hello, this is a very tough question. Some cosmologists, physicists that study the origin of the universe, believe that the space-time continuum is being created at the same time as the matter of the universe is expanding. Others, like Einstein, believed that the universe was infinite but with a curvature like a sphere or a giant saddle. It is this sphere (in 4 dimensions!) that is expanding.
Wow, that’s a toughy.
I’ve heard of other theories about particles outside the “balloon” of our universe which are constantly coming in and out of existence creating the pressure to suck our universe outwards
Some others believe that our universe exists as only one of many universes, which lie beside each other!