system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If nothing can travel faster than light than why light is unable to escape the blackholes?
gpt
If you think of space like a big, flat, rubber sheet, then you pinch a part of that sheet and pull it down some, the dip you get in the sheet is how gravity works.  That's a "gravity well".

Now roll a marble along that sheet - that's light.  The marble encounters the well, maybe straight on, maybe at an angle, and depending on how it hits the gravity well, the marble may come out straight or it may change course (like a golf ball on a putting green where it clips the hole)

Now - PULL THAT SHEET DOWN SUPER HARD.  Make the gravity well go WAYYYYYY down.  Further away you get a gradual slope but right at the center?  A sheer pit.

No matter how fast you shoot that marble, it's gonna hit that gentle slope first, so it's gonna angle down.  Then it hits the steeper points, and its going down already, so if it hits a deep enough part of the well, there's just no way for it to go back up.  It might kinda fly across the hole but its gonna hit the wall on the other side and bounce, and keep going down as it does so.

That's a black hole - light crosses a certain threshold and it doesn't matter how fast its going, its going down.