The concept of warping space-time as an advanced propulsion technology is a very common one in science fiction; probably the best known example is found in “Star Trek”. This technology would allow faster-than-light travel, and, maybe even more relevant for astronomy, represent a powerful window to the Universe both in terms of space and time. Ranging from Star Trek’s “Voyager” pilot episodes to Larry Niven’s “The Mote in God’s Eye” and R.J. Sawyer’s “Starplex”, warping is one of the most common ways of circumventing the enormous travel times which would otherwise render science fiction a very boring genre. In the “Star Trek” world, the primary propulsion system used by most faster-than-light interstellar spacecraft is the warp drive. The system used by Federation starships employs the controlled annihilation of matter and anti-matter, regulated by dilithium crystals, to generate the tremendous power required to warp space and travel faster than the speed of light.

A warp drive is basically a mechanism using exotic matter with negative energy density for warping space-time in such a way that an object could move faster than light. In 1994, Miguel Alcubierre worked out a space-time geometry which describes such a warp drive. The warp in space-time makes it possible for an object to go faster than the speed of light while remaining on a time-like curve.

Rodenberry takes full advantage of the concept of the warp drive in his “Star Trek” odyssey to transport us to the edges of our Universe. In the “Avatar”, Poul Anderson shows how humankind could travel between stars by using the exotic relativistic effect of massive rotating cylinders on the space-time metric surrounding them, as predicted by the Theory of General Relativity. The latter allows us to consider some orbits around a massive rotating cylinder which are “instantaneously” connected to other orbits around another massive spinning cylinder located at an arbitrary distance from the first cylinder. From a technological point of view, the main problem is, of course, to build a network of such rotating cylinders spread throughout the entire Universe.

From the physics perspective, the relationships between space and time in a particular region are confined by the realms of General Relativity. A basic example is a “wormhole”, which could use exotic matter to causally connect two distant locations in space. A hypothetical spaceship could enter one “mouth” of the wormhole and exit from the other very distant “mouth”. Although the travelling issue is certainly the most inspiring aspect, wormholes, if they exist, could prove to be astonishing tools for seeing (in a broader sense) other and older parts of a remote Universe.