Originally Posted by rwald

If I'm not mistaken, the more popular theory is that the universe in infinite in size. If that were the case, then there would be no edge, and no conceptual problem. The alternative, that the universe is finite in size, would be resolved in almost the same way that flat-Earth theory was: the left edge would wrap around to the right edge, and the top edge would wrap around to the bottom edge (making a torus, not a sphere, but you get the idea). Actually, the shape of the universe wouldn't necessarily need to be a torus (especially because it's got an extra dimension), but that's probably the easiest to visualize.