Imagine zooming through space, borne on the wings of propulsion that has neither moving parts nor any sort of emissions. A drive powered entirely by electromagnetic radiation. Sounds like the stuff of science fiction, right? But not only is it the stuff of science fact , but a working prototype exists in a rather unlikely place: the South coast of England.
Former spacecraft engineer Roger Shawyer has developed a drive that generates thrust from microwaves. A device the size of a suitcase could reputedly propel a modern day spacecraft with no problem.
Most of the science involved here is over my head, but what struck me was that a large portion of the drive's operation is derived from the effects of relativity.
How can photons confined inside a cavity make the cavity move? This is where relativity and the strange nature of light come in. Since the microwave photons in the waveguide are travelling close to the speed of light, any attempt to resolve the forces they generate must take account of Einstein's special theory of relativity. This says that the microwaves move in their own frame of reference. In other words they move independently of the cavity - as if they are outside it. As a result, the microwaves themselves exert a push on the cavity.flying carsSweet
[via Slashdot ]