system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How gravity works

I know what it does, but why?
gpt
We don't know why, but we think we do know how.

Imagine a corridor that curves gently around a corner. If you walk in a straight line down the corridor, eventually you will come in contact with the wall. If you keep walking, you will be pushed along the curved wall, making you walk in a curved path.

Gravity works a bit like that. All heavy objects, like planets, cause the space (actually, spacetime, but that's beyond an ELI5 expanation) around them to bend. Things normally move in straight lines, but when something passes through the bent space around the heavy object, instead of flying straight past, it is forced to follow the bent path, just as you are forced to follow the bend in the corridor.

This applies to all objects in the universe that have mass, but the effect is very very tiny for small things like you and me. It's only really noticeable for very heavy things like stars and planets.