Could light extend beyond the edge of the universe?

That's good thinking--out of the box, as it were. But, from what I know of cosmology, there can't be light outside the universe. We tend to think of the universe as the "populated" bit of space that's expanding into an infinite expanse of empty space--but what's really happening is that space itself is expanding. There IS no "outside" the universe (it's sort of like asking what's north of the north pole). Even hard vacuum has things going through it: light, gravity, the occasional atom. But there's no "there" outside the universe. You couldn't fly a spaceship beyond the universe, for instance.