Faster than light

Faster-than-light (FTL) communications and travel are the propagation of information or matter faster than the speed of light. Superluminal is an adjective used for a speed or velocity exceeding the speed of light.

With the old laws of physics, Einstein's special theory of relativity says that only particles with zero rest mass (like photons) may travel at the speed of light. Mass gains weight as it accelerates and as it approaches the speed of light, it becomes infinitely heavy. There is also increasingly severe time dilation experienced by the traveler approaching the speed of light, and everything else ages as you travel. Ways around these problems had to found via technology to effectively travel "faster than light" using spacetime warp displacement, hyperspace lanes, or natural cosmological structures like wormholes.

Tachyons, particles whose speed have to be much faster than light, are used once the new laws of physics are discovered.

FTL drives are significant for Type II civilizations. Beyond that, instantaneous methods of travel are used unless traversable wormholes are discovered first.