Why doesn the universe look like a torus in space rather than an expanding sphere?
One of the hardest things to do is to try to visualize what the universe might look like on its largest scales. The only guide we have is Einstein’s theory of general relativity, and until such time as this theory is shown to be incorrect, it is our only best shot at visualizing what is going on. The universe does not exist, embedded in some larger space, but contains 3- dimensional space within itself. This isn’t philosophy, but hard physics. The universe is not an expanding sphere in space, nor is it a torus or any other shape in space. Instead, it is the space itself that for a closed universe is bent around into a finite spherical volume. At any instant in cosmic time, the shape of space in a closed universe is that of a hypersphere with a finite 3-dimensional space. At future instants in time, the radius of this hypersphere increases or ‘stretches’. The larger picture is that of a 4- dimensional hypersphere, and it is this 4-dimensional shape which is a solution of Einstein’s rela
