"Spooky" quantum entanglement connects two particles so that actions performed on one reflect on the other.

 

 Now, scientists propose testing entanglement over the greatest distance yet via an experiment on the International Space Station.

 

Until now, entanglement has been established on relatively small scales in labs on Earth. But now physicists propose sending half of an entangled particle pair to the space station, which orbits about 250 miles (400 kilometers) above the planet.

"According to quantum physics, entanglement is independent of distance," physicist Rupert Ursin of the Austrian Academy of Sciences said in a statement. "Our proposed Bell-type experiment will show that particles are entangled, over large distances — around 500 km — for the very first time in an experiment."