Every Star Trek fan knows how to travel faster than the speed of light. By means of a warp drive that generates a warp bubble around the spaceship, the traveler can cover thousands of light years in a few hours. Miguel Alcubierre found a space-time metric that not only does this job but is also consistent with Einstein's general theory of relativity. The key idea is to contract space-time in front of the traveler and to expand it behind. Here, you can manipulate the size and the thickness of the warp bubble yourself.