Experiment finds evidence for the Majorana fermion, a particle that's its own antiparticle

In 1928, physicist Paul Dirac made the stunning prediction that every fundamental particle in the universe has an antiparticle - its identical twin but with opposite charge. When particle and antiparticle met they would be annihilated, releasing a poof of energy. Sure enough, a few years later the first antimatter particle - the electron's opposite, the positron - was discovered, and antimatter quickly became part of popular culture.