Antimatter must exist!
Paul Dirac was studying these equations at Cambridge University in 1928, when he realised something extraordinary. When he solved the equations which describe how an electron behaves, he found there was not one solution, but two.
The first solution described a normal electron, as everyone had expected, but the second appeared to describe a new type of electron: one with a positive charge.
This was an amazing idea. Nobody had ever heard of, or even thought of, an electron with a positive charge. Still, Dirac was quite sure he’d got his maths right: this new type of electron had to exist. He called it the positive electron.
Paul Dirac was predicting the existence of an entirely unknown type of matter. Was he right?
At that stage nobody knew.