Who first discovered antimatter?

   Physicist Paul A. M. Dirac first deduced in 1928 that all matter should exist in both positive and negative states. He applied his discovery first to electrons and soon was proven correct when antielectrons, or positrons, were discovered. These positively charged electrons were first detected in 1932 by American physicist Carl Anderson. Anderson tracked particles bouncing off a lead plate and found that while all the elec­trons were deflected in one direction, there was another type of particle that headed off in the opposite direction. This particle had all the same characteristics as an elec­tron, except for its positive charge. Anderson gave it the name "positron." For the dis­covery of the positron, Dirac and Anderson shared the Nobel Prize. Two decades later the antiproton and antineutron were discovered. Naturally occurring positrons were detected in 1979, high above Texas, during a balloon experiment.