In 1931, the shy, brilliant British physicist Paul Dirac predicted the existence of a weird class of particles called antimatter. When Carl Anderson of Caltech quickly proved him right, Dirac should have become a household name, but his aversion to publicity—he almost turned down the Nobel Prize—discouraged media attention. Today he is known only among serious science fans, even though antimatter lies at the heart of some of the deepest mysteries in modern physics.
Despite its esoteric connotations, antimatter is stone-simple to understand. In most respects—mass, for instance—particles of antimatter are identical to those of matter. The primary difference is that their electric charges are reversed. An antimatter nucleus is negative instead of positive, and it is orbited by positrons, electrons that are positive instead of negative.
In fact, the two are so much alike that nobody can explain why matter so thoroughly dominates its near twin. Nearly every model ...
