Actually, tachyons aren't just sci-fi, they are hypothesized (but not proven) from real physics. Relativity does not say that nothing can travel faster than the speed of light, just that nothing can accelerate (or decelerate) through the speed of light. Therefore, it is theoretically possible to have a particle that always travels FTL, aka tachyons. <br /><br />Star Trek loves them because they're not pure fantasy<br /><br />