In previous posts in this blog I have mentioned various procedures often used by the authors of science fiction novels to make interstellar travel almost as simple and brief as today's airplane trips to different points on Earth. One of these procedures consists of disintegrating the ship and reintegrating it into the universe of tachyons: hypothetical particles, compatible with the theory of relativity, that would always travel at speeds greater than the speed of light. Thus it would be possible (in principle) to travel very fast to the point we are interested to go to, reintegrate the ship into the world of tardions (in other words, into our world), and presto! We have traveled faster than the speed of light.
In fact, the authors of these novels (of which I am one) don’t usually go into detail about what the world of tachyons would be like. We simply assume three necessary conditions for interstellar travel to be possible: