Entanglement

In quantum physics, particles with entangled properties remain connected by a strange link however widely they are separated. Measuring and ‘resolving’ the properties of one causes the other to instantaneously resolve itself in the other direction, with no time needed for a message to travel between them. Einstein called this effect ‘spooky action at a distance’ – the laws of physics seem to permit it because it can’t be used to send information at faster-than-light speeds.