Tachyon, << TAK ee on, >> is a hypothetical elementary particle. An elementary particle is a subatomic particle that has no known smaller parts. If tachyons exist in nature, they never stand still but always move at speeds greater than the speed of light. Light travels 186,282 miles (299,792 kilometers) per second. The faster a tachyon travels, the lower its energy. The name tachyon comes from a Greek word meaning swift.
According to the special theory of relativity, ordinary matter can move only at speeds less than the speed of light. The German-American physicist Albert Einstein published the special theory of relativity in 1905. But in 1962, several physicists realized that the existence of particles that travel faster than light is not necessarily incompatible with Einstein’s theory. No convincing experimental evidence has been found for the existence of tachyons.
