Einstein–Podolsky–Rosen paradox
Okay kiddo, imagine you have two boxes, one red and one blue, and inside each box there is a toy. If I give the red box to your friend who lives in another state, and you keep the blue box with you, do you know what toy your friend has in the red box?
No, of course not, because you can't see inside the box! But let's pretend that the toy in the red box is a teddy bear, and the toy in your blue box is a toy car. According to science, before you and your friend opened the boxes to see what was inside, each toy was in what we call a "superposition" state - which means it was both a teddy bear and a toy car at the same time. Sounds crazy, right?
But that's exactly what happens with tiny particles called "photons" that are paired together. Scientists Eugene Wigner, John Bell, Albert Einstein, Boris Podolsky, and Nathan Rosen came up with a thought experiment called the Einstein-Podolsky-Rosen paradox to try and understand this concept.
They imagined that two photons were "entangled" - which means that whatever happens to one photon immediately affects the other, even if they are very far away from each other (just like how the toy in the red box is connected to the toy in the blue box, even though they are in different places).
Now, let's say that we measure one of the photons and find out that it has a specific property - let's call it "spin". According to science, the other photon should have the opposite spin. So if the first photon has "up" spin, the second photon should have "down" spin and vice versa.
But the Einstein-Podolsky-Rosen paradox says that if we then measure the spin of the second photon, it will always be the same as the first, no matter how far apart they are. This means that the photons must already "know" what spin they will have when they are measured, even though they are in a superposition state.
This idea challenged scientists' understanding of reality and sparked many debates and experiments to try and understand how entangled particles can have an effect on each other, no matter how far apart they are. It's still a mystery that scientists are trying to solve today!
No, of course not, because you can't see inside the box! But let's pretend that the toy in the red box is a teddy bear, and the toy in your blue box is a toy car. According to science, before you and your friend opened the boxes to see what was inside, each toy was in what we call a "superposition" state - which means it was both a teddy bear and a toy car at the same time. Sounds crazy, right?
But that's exactly what happens with tiny particles called "photons" that are paired together. Scientists Eugene Wigner, John Bell, Albert Einstein, Boris Podolsky, and Nathan Rosen came up with a thought experiment called the Einstein-Podolsky-Rosen paradox to try and understand this concept.
They imagined that two photons were "entangled" - which means that whatever happens to one photon immediately affects the other, even if they are very far away from each other (just like how the toy in the red box is connected to the toy in the blue box, even though they are in different places).
Now, let's say that we measure one of the photons and find out that it has a specific property - let's call it "spin". According to science, the other photon should have the opposite spin. So if the first photon has "up" spin, the second photon should have "down" spin and vice versa.
But the Einstein-Podolsky-Rosen paradox says that if we then measure the spin of the second photon, it will always be the same as the first, no matter how far apart they are. This means that the photons must already "know" what spin they will have when they are measured, even though they are in a superposition state.
This idea challenged scientists' understanding of reality and sparked many debates and experiments to try and understand how entangled particles can have an effect on each other, no matter how far apart they are. It's still a mystery that scientists are trying to solve today!