An article for the Sept. 22, 2007 issue of New Scientist magazine

Warp drive will kick up serious radiation

It's one thing to boldly go faster than light by manipulating space-time, but quite another to deal with the "exhaust"

WANT to zip across the galaxy, boldly going where no one has gone before? Then make sure your spaceship is fitted with enough shielding to protect you from all the radiation your "warp drive" travels will expose you to. So concludes Pedro González-Díaz at the Institute of Fundamental Physics and Mathematics in Madrid, Spain.

The problem is that no one has a clue how to make a warp drive,. In 1994, physicist Miguel Alcubierre of the University of Wales in Cardiff, UK, proposed that a spaceship could travel at speeds way beyond the speed of light. The way to make the necessary warp drive, he suggested, was to create a protective bubble with space-time bunched up in front of it and stretched out behind it.

Three years later, however, physicists calculated that such manipulations of space-time required more mass than is contained in the known universe. Such paltry problems did not perturb "Alcubierre drive" enthusiasts. New and improved bunchings and stretchings of space-time have since been devised and, in 2000, González-Díaz proposed his own solution: a mathematical configuration of space-time that he claimed was closer to being physically possible, if still not technologically feasible.

González-Díaz has now shown that his "warp bubble" effectively acts like the edge of a mini-universe, containing a space-time similar to that of the observable cosmos. This analogy, he hopes, may make warp-drive solutions more palatable to mainstream physics and may even mean that our universe could actually be a passenger inside its own "warp drive" bubble.

One hiccup, according to González-Díaz's calculations, is that the faster one of his imagined spaceships goes, the more radiation it would encounter from space itself (Physics Letters B, DOI: 10.1016/j.physletb.2007.08.008).

Alcubierre drives, as well as wormholes, are actually predicted by relativity. They may be outlandish, says González-Díaz, but so were black holes at one time. "Warp drives correspond to what one can consider real, well-established theoretical physics."

Roger Penrose, visiting professor of physics at Pennsylvania State University in University Park, agrees, "but only if we take it in the right spirit, as a theoretical exploration of the significance of Einstein's theory, not as a potential means for actually building faster-than-light spaceships."


By Mark Anderson


(cc) image by Randy Lemoine