TACHYON

A tachyon is a hypothetical subatomic particle whose velocity always exceeds that of light. The existence of the tachyon, though not experimentally established, appears consistent with the theory of relativity, which was originally thought to apply only to particles traveling at or less than the speed of light. Just as an ordinary particle such as an electron can exist only at speeds less than that of light, so a tachyon could exist only at speeds above that of light, at which point it's mass would be real and positive. Upon losing energy, a tachyon would accelerate; the faster it travelled, the less energy it would have. A zero-energy tachyon is "transcendent" or moves infintely fast. This has profound consequences. For example, if there were electrically charged tachyons, they would move faster than the speed of light in a vacuum and they should produce radiation. This would lower their energy causing them to accelerate more! Charged tachyons would probably lead to a runaway reaction releasing an arbitrarily large amount of energy. No tachyons have definitely been found and most physicts doubt their existence, but they have been mathematically hypothesized. It would require an infinite amount of energy to slow down a tachyon to the speed of light. If tachyons do exist, it could allow for faster than light communication and perhaps even to send messages through time. These massless quasiparticles can go faster than light only because they always travel at "superluminal" speed from the moment of their creation in subatomic collisions or disentegration. The existence of tachyons can lead to a "time travel" paradox. A claim of tachyon detection would require extraordinary evidence. What tachyons really demonstrate is the importance of imagination in our ongoing quest to understand the universe. They may not exist, and if they do we may have no hope ever measuring one.