As practical science marches on, more and more science fiction technology becomes plausible. A few years ago, a Mexican physicist named Michael Alcubierre postulated a mechanism to make warp drives possible, limited only by an enormous energy requirement. How much energy? According to Baylor University physicists if the entire mass of Jupiter were converted into energy, that would be enough to make the Alcubierre Drive possible. For years, the Alcubierre Drive has entertained researchers with various designs either attempting to reduce the energy requirements or simply to theorize what could be done. Some proposed using metamaterials to attain speeds upwards of 25% faster than light. The main premise of the design is summarized nicely by NASA:
Although Special Relativity forbids objects to move faster than light within spacetime, it is unknown how fast spacetime itself can move. To use an analogy, imagine you are on one of those moving sidewalks that can be found in some airports. The Alcubierre warp drive is like one of those moving sidewalks. Although there may be a limit to how fast one can walk across the floor (analogous to the light speed limit), what about if you are on a moving section of floor that moves faster than you can walk (analogous to a moving section of spacetime)? In the case of the Alcubierre warp drive, this moving section of spacetime is created by expanding spacetime behind the ship (analogous to where the sidewalk emerges from underneath the floor), and by contracting spacetime in front of the ship (analogous to where the sidewalk goes back into the floor). The idea of expanding spacetime is not new. Using the “Inflationary Universe” perspective, for example, it is thought that spacetime expanded faster than the speed of light during the early moments of the Big Bang.
The huge energy requirement comes from surrounding a small spacecraft with a large ring. The ring (that scientists believe should be made of metamaterials) needs to create pulsed, negative energy in order to warp the space time around it and create the bubble for the contraption to slip through. Still, the energy requirements were enormous until NASA presented a new ring design at the 100 Year Starship conference. Their proposed calculations show that by changing from a flat ring into a donut ring, the energy requirement is substantially reduced (equal to converting a large vehicle into energy instead of a super giant planet). Additionally, NASA proposes that oscillating the energy ring will further reduce the requirement and has begun small scale laboratory testing.
Just as additional reading for the interested, here are two reports on the Alcubierre Drive (though they precede the NASA calculations). The Alcubierre Warp Drive in Higher Dimensional Spacetime (pdf) and The Alcubierre Warp Drive I particularly liked the “implications” from the second paper that wondered what happened to physical matter (like other living things’ homes) when a warp drive passed by and stretched their space time fabric.
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