Just Too Cool not to Pass On

The final image of the progression out to the "edge" of the known universe is a bit misleading. The mere fact that I had to use the word "edge" is evidence of the difficulty. Mathematically, the universe is finite but unbounded; it has no edge. It's that unboundedness that's hard to envision. You can think of it as a sphere similar to that image but it's not spherical - it's more like a 4-dimensional sheet stretched over a curved surface - maybe that of a sphere, maybe something more complex. Does that clear it up for you? You're welcome.