system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What happens to gravity in the center of the earth?

Ok, hypothetically there is an elevator that travels exactly through the center of the Earth. What happens to gravity as you travel? At what point would it reverse in perspective to the gravitational pull when you entered the elevator?
gpt
It would gradually decrease as you went down, until you were weightless at the exact centre of the Earth. Then it would reverse and gradually increase again until you got back to the surface.

The really weird case is if Earth were in fact a hollow shell rather than a solid planet. Then as soon as you got inside the shell, the gravity from different parts of the shell would cancel out and you'd be weightless anywhere inside the shell.