Faster-than-light

Faster-than-light (also superluminal or FTL) communications and travel are staples of the science fiction genre. However, according to currently understood physics, these concepts require exotic conditions that current technology can't establish, and that may be directly forbidden by more complete models of the universe's physical laws. Current theories of physics suggest that FTL travel or communication would necessarily involve time travel and thus would almost certainly cause problems with causality.

Tachyons

In special relativity, while it is impossible to accelerate an object to the speed of light, or for a massive object to move at the speed of light, it is not impossible for an object to exist which always moves faster than light. The hypothetical elementary particles that have this property are called tachyons. Their existence has neither been proven nor disproven. If they exist and can interact with normal matter, they would allow causality violations. If they exist but cannot interact with normal matter, their existence cannot be proven, so they might as well not exist.

Related Topics:
Elementary particle - Tachyon - Might as well not exist

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