In 1928, Paul Dirac developed an equation (fittingly called the Dirac equation) that predicted the behaviour of electrons near the speed of light.
But the Dirac equation had a surprising by-product. It could be applied equally well to something that no one had ever seen: a positively charged electron. In other words, the equation implied the existence of antimatter. In 1932, the first positrons — positively charged anti-electrons — were found in cloud chambers.
Today, antimatter is an integral part of physics. It’s essential to the particle physics done at colliders like CERN. The puzzle of what happened to the antimatter — which, according to theory, should have been produced at the big bang — is a driving question in modern cosmology.
And though it sounds like science-fiction (after all, it did power the Starship Enterprise), antimatter has some surprising practical applications. Positrons are the basis of Positron Emission Tomography, or PET scans, a powerful tool in medical science.
Positrons can be used to detect defects in materials, such as semiconductor wafers, that no other probe is sensitive enough to see. They can also be added as a tag to track small, fast-moving particles — everything from drugs moving in the bloodstream to lubricant flowing through jet engines.
Antimatter is still mostly a technology of the future — mainly because it costs trillions of dollars to produce a single gram of it — but perhaps one day the secret side of Dirac’s equation will power ships to the stars.
Check out The Riddle of Antimatter: