Einstein called it "spooky action at a distance:" one particle can instantaneously tell what another is doing without being anywhere near it. It's called quantum entanglement. And now NIST physicists have brought this effect to the real world.
They demonstrated this effect using two "entangled" mechanical oscillators. (A mechanical oscillator can be anything from a pendulum to a watch spring to a guitar string. Here, it's vibrating atoms.) First, they separated two entangled atoms from each other. Then the scientists prodded one vibrating atom of the pair, and the other vibrating atom acted like it was being prodded too - despite being nowhere near the first one. The two seem to be almost telepathically communicating with each other, faster than the speed of light.
This isn't the first strange experiment in quantum entanglement. Entangled photon pairs have been used to take ghostly photos through opaque barriers. Entanglement is also a key part of the classic Schrodinger's Cat thought experiment. But this experiment shows that entanglement isn't limited to immeasurable scales: one day, quantum computers might harness this effect for instant, efficient processing.
And there are even cooler implications from this experiment: In Philip Pullman's The Amber Spyglass, spies can instantaneously converse with their commanders by composing messages on a resonator entangled with a receiver worlds away. This recent experiment shows that Pullman's idea of large scale entanglement is theoretically possible, making faster-than-light communication more than just speculation.
Entangled Mechanical Oscillators [arXiv.org]
For further reading: "Ghost" Photographs Created via Quantum Entanglement