If you could send a text message faster than the speed of light, you could theoretically warn yourself not to send it. This is the mind-bending concept of the Tachyonic Antitelephone. In theoretical physics, this is a hypothetical device that uses "tachyons"—particles that travel faster than light—to communicate with the past. According to Einstein's Special Relativity, there is no universal "now." Time is relative to your speed. If a particle moves faster than light (FTL), there will always be