The quantum realm is full of seemingly impossible things. But one of the strangest has to be entanglement.
Entanglement is a special way of linking up particles. When two particles become entangled, their features are perfectly in sync. Such features might include their position or speed. If you measure the properties of one particle, you automatically know the properties of the other. And whatever happens to one will also affect the other.
This is true no matter how far apart two entangled particles are. They could be on opposite sides of the planet, the solar system or even the universe. Even then, observing one would still instantly tell you what’s going on with the other.
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Scientists first proposed entanglement was possible in the 1930s. But not everyone was on board with the idea. One famous skeptic was Albert Einstein. His problem was that with entangled particles, it would be possible to instantly tell someone what’s happening infinitely far away. This would suggest that information can travel infinitely fast. And nothing, not even information, is supposed to be able to travel faster than the speed of light. For that reason, Einstein dubbed the idea of entanglement “spooky action at a distance.”
Lab experiments have since shown that particles can indeed become entangled. Those experiments won three researchers the 2022 Nobel Prize in physics. Scientists have entangled light particles, or photons. Plus electrons, atoms and even molecules. Such synced-up particles could be used to build quantum computers. Using quantum bits, or qubits, those devices may solve problems no ordinary computer can.
So Einstein might have been wrong about entanglement being real. But he was right about it being pretty spooky stuff.
Want to know more? We’ve got some stories to get you started:
Experiments on ‘entangled’ quantum particles won the physics Nobel Prize The winners of the 2022 Nobel Prize in physics showed that entanglement happens in real life. (10/5/2022) Readability: 7.9
Here’s why scientists want a good quantum computer These machines could tackle big problems in climate, medicine and more. But the tech is still in its infancy — and runs on truly strange physics. (5/30/2024) Readability: 7.9
The quantum world is mind-bogglingly weird At the smallest scales, particles behave very strange ways that scientists are still trying to understand. (9/14/2017) Readability: 7.3
Let’s unpack what exactly entanglement is — and why it might be important to the very fabric of the cosmos.
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Activities
Play Uno with a quantum twist! This fun variant on this classic card game with “entangled” players adds an extra challenge.
