Physics Says No to Warp Drives, but NASA Says Maybe

There’s been a lot of buzz around in the Internets lately about the possible warp drive NASA scientists are working on. A warp drive isn’t, strictly speaking, a new idea; it’s been a staple of science fiction for ages, but it’s been relegated to the realm of fantasy because its practical application hinges on finding and exploiting loopholes in physics to move a spacecraft through manipulated space-time.

But now physicists are finding some potentially plausible science behind a potentially feasible warp drive. At least,  Harold White of NASA’s Johnson Space Center thinks it’s plausible. White boldly announced at the 100 Year Starship symposium two months ago, a meeting centered on discussing the problems of interstellar flight, that faster than light travel might be possible. Emphasis on “might.”

NASA’s position on warp drives, according to the agency’s website, is a little less enthusiastic. It’s summed up pretty nicely in this graphic that places the maturity of warp drive firmly in the “speculation” area. The problem is that breaking the light barrier isn’t at all like breaking the sound barrier. The sound barrier–properly, the aerodynamic effects of pressure waves interacting with a body as it approaches the speed of sound–was broken with a cleverly engineered aircraft and an at-the-time state of the art rocket engine.

Bell’s X-1 was, importantly, a physical aircraft made of matter, not made of sound. But the atoms and molecules that make up all matter are connected by electromagnetic fields, and that’s the same stuff that light is made of. So when it comes to breaking the light barrier, it’s like breaking through light with light (sort of… ask Brian Greene). As NASA poses the question, “How can an object travel faster than that which links its atoms?” It’s a very different matter.

The rules of special relativity also pose a problem. Einstein said that the distance you’ll travel depends on how fast you move and how long you’re moving, but no matter how fast you’re moving you’ll always see the speed of light as being the same, which, when talking about going faster than light, makes for a bit of a pickle.

Another issue special relativity brings up is the light speed barrier. Moving takes energy, and the faster you move the more energy you use. So, theoretically, to move at the cosmic speed limit of light you need an infinite amount of energy. That’s a distinct barrier if there ever was one, and it’s the barrier Mexican physicist Miguel Alcubierre ran into headfirst in 1994.

Alcubierre designed a faster-than-light spacecraft. It was a football-shape vehicle encircled by a large ring. The ring would make space-time warp, contracting the space in front of the spacecraft and expanding the space behind it. The space in front contracting would give the spacecraft someplace to go while the space behind it expanding after being compressed would propel the spacecraft forward. The combined effect of this simultaneous compression and expansion would create a “warp bubble.” Space-time would, in effect, move around the spacecraft. Passengers would see things as though they were moving, but in fact they would be completely stationary. The spacecraft would move faster than light without having to move from its physical starting point in space.

But Alcubierre’s idea was shelved. Further calculations revealed that making this kind of spacecraft work, that is, generating that warp bubble, would take prohibitive amounts of energy. Like, a minimum amount of energy equal to the mass-energy of the planet Jupiter levels of prohibitive energy. Space-time is stiff, and moving it around a spacecraft isn’t easy.

White wasn’t about to let prohibitive energy needs kill the dream of a warp drive. Over the last two decades, physicists, White among them, have found some ways to adjust Alcubierre’s design to bring a warp drive closer to reality. White investigated what would happen if the shape of the ring around Alcubierre’s proposed spacecraft was more rounded than flat – think shifting from a belt-shaped loop to a donut shape. Then he looked at what would happen if that donut-like ring oscillated, moving the warp bubble with it.

Turns out, this little change drastically reduces the amount of energy needed to create a warp bubble. Instead of the equivalent mass-energy of Jupiter, this design needs an energy mass of about the size of one Voyager spacecraft. And if the intensity of the warp bubble can oscillate as well, that’s even better for energy consumption.

So this is what White and his NASA colleagues are working on in a laboratory. They’ve set up a White-Juday Warp Field Interferometer at the Johnson Space Center, which essentially creates a laser interferometer that instigates micro versions of space-time warps. It’s nowhere near enough of a warp to move a spacecraft, but it’s a start.

Whatever happens, whether or not White and his colleagues can find a way to warp space-time and punch some holes in the theory of special relativity, we won’t be wooshing instantly from one end of the universe to the other any time soon. Sorry, warp drive dreamers, but if you want to travel amongst distance stars, I'd start thinking about how to freeze yourself for a few hundred years first.