How do black holes form and what happens at their event horizon?

A black hole is like a cosmic vacuum cleaner that forms when a star gets too heavy and collapses.

Imagine your favorite toy, say, a giant ball, rolling down a hill. If it's just the right size, it rolls smoothly. But if you make it super heavy, like adding ten more balls to it all at once, it might crash into the ground really fast. That’s what happens with a star when it runs out of fuel: it can’t hold itself up anymore and collapses.

If the star is really big, like 20 times bigger than our Sun, it collapses so strongly that it becomes a black hole, which is like a super-dense ball made of crushed matter. Everything nearby gets pulled toward it, just like how your socks get sucked into the washing machine when you forget to put them in a laundry bag.

The event horizon is the edge of a black hole, kind of like the point where the washing machine door closes and your socks are gone. Once something crosses that line, it can’t come back out. It gets pulled in so strongly that even light can't escape, which makes the black hole appear completely dark.

It’s like if you dropped a toy into the deepest part of a pool, you’d never see it again. That's what happens to anything near a black hole!