ELI5: Explain Like I'm 5

Quantum nonlocality

Quantum nonlocality is about things in the world of really, really small (atoms and particles) that don't follow the rules we're used to in the world of everyday things.

Imagine you're playing catch with a friend in a park. You throw a ball to your friend, who catches it. From the moment you throw the ball, you know where it is, and when it gets to your friend, they know where it is. But with particles, things are different.

Quantum physicists have found that these really tiny particles can be in two places at the same time. Yes, that sounds crazy, but it's true! This is called "superposition." And even weirder, these particles can be connected to each other, even when they're really far apart. This is called "entanglement."

When two particles are entangled, they become linked in such a way that whatever happens to one particle affects the other one, no matter how far apart they are. Imagine having a magic ball that's entangled with another magic ball held by one of your friends. We can't see the balls, but if you squeeze your ball, your friend's ball will automatically squeeze at the same time, even if your friend and his ball are on the other side of the world!

This is where quantum nonlocality comes in. It seems like there is some sort of connection between the two particles that is faster than the speed of light, which is impossible according to what we know so far. It's like having a phone conversation with your friend on the moon and being able to hear their voice as soon as they finish speaking, even though sound travels much slower than the speed of light.

Scientists are still trying to figure out why and how this happens, but for now, we can marvel at the strange and amazing properties of the subatomic world.