system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 The "edge" of the universe, and why there isn't one.
gpt
The best approximate explanation I've heard was from an astronomy 101 professor. He described it like so: imagine a stick figure, drawn on a chalk board. The stick man is limited in space by the edge of the board, so there is an edge to his universe. But if the stick figure is drawn on a balloon and the balloon is being inflated (infinitely, it's a very stretchy balloon), he'll never reach the edge, because there isn't one, and the universe is constantly growing so the distance around it is constantly increasing. He'll never come back around to the place he started, because his speed is limited and the balloon is inflating too fast. This also explains why we can't point out where the center of the universe is, any more than the two-dimensional man can point to the center of the balloon. Bear in mind, this is probably a gross over-simplification of the physics, but you're five, so don't worry about it. Go play outside now and let daddy enjoy his scotch.