> The real reason is that the space-time curvature does simply not provide a way for the light to go back. Same reason you can't go to the end of the universe i

> The real reason is that the space-time curvature does simply not provide a way for the light to go back. Same reason you can't go to the end of the universe if the universe would be a sphere. Or the same reason you can't travel to yesterday - there are simply no directions in which to point yourself in order to get there.