Quantum theory predicts that observing and object can affect another object at that precise moment, even if it is on the other side of the universe. It’s a phenomenom that Einstein did not believe in. But in a recent experiment two electrons separated by 1,3 km. on the campus of Delft Technical University in Holland were able to communicate in an “invisible” and instantaneous way. This advance, which included the participation of the Photonic Science Institute of Barcelona, can be applied to quantum cryptography. It also confirms how strange our universe is.