Our everyday experience of interstellar travel usually comes in the shape of the U.S.S. Enterprise zooming around the galaxy at warp speed. Unfortunately, the warp drive is primarily used as a tool by scriptwriters to condense the extreme interstellar distances into hour-long episodes. But there's a growing field of study that actually attaches some physics — albeit rather "exotic" physics — to superluminal (a.k.a. faster-than-light) travel.
Earlier this month, scientists and engineers were able to discuss their warp-drive concepts at the 100 Year Starship Symposium in Houston, Texas, and there was some good news for sci-fi fans everywhere: the warp drive might not be as energy hungry as previous studies suggested.
Sonny White of NASA's Johnson Space Center presented his calculations on the energies required to travel faster than Einstein's famous speed limit: the speed of light. By White's reckoning, his design of starship — that is "adjusted into more of a rounded doughnut, as opposed to a flat ring" and oscillates the warp intensity — could be powered by the approximate mass-energy of the Voyager 1 space probe.
Although "the mass-energy of the Voyager 1 space probe" may not sound like much, if you convert the 722 kilogram Voyager mass into raw energy (using Einstein's famous mass-energy equivalence equation: E=mc2), White's warp drive would require 6.5×1019 Joules (65 exajoules) to create a warp bubble. That's nearly the entire annual energy consumption of the United States.
Clearly, this monstrous energy requirement isn't practical, but it's one heck of an improvement over previous estimates.
In 1994, physicist Miguel Alcubierre was widely credited to be the first to put some real physics into the warp drive. Although Star Trek would have us believe that you just need some dilithium crystals and a starship captain to point his finger, saying "Engage," Alcubierre discovered that the warp drive was theoretically possible, but it would need all the energy in the entire universe to function.
Alcubierre realized that for a spacecraft to travel faster than the speed of light — something that Einstein's Special Theory of Relativity prohibits — the spacecraft would need to somehow create a warp "bubble" around it. This would allow the spacecraft to be contained within its own region of spacetime. If the bubble can be controlled, then the light-speed limit can be exceeded in 'normal' space — the spacecraft itself would be stationary whereas the bubble in spacetime will zip around at, effectively, infinite speed.
As described by Eric W. Davis, senior research physicist at the Institute of Advanced Studies in Austin, Texas, and co-author of Frontiers of Propulsion Science, the warp drive can be envisaged as a means of "surfing" through spacetime:
Although Alcubierre's calculations showed that unimaginably huge amounts of energy would be needed to create this warp bubble, recently, Richard Obousy, co-founder and president of Icarus Interstellar (a key partner of the 100YSS), used our new understandings of quantum mechanics and applied them to the warp drive.
Obousy's approach is to manipulate dark energy — the mysterious force that appears to permeate the entire Universe, causing it to expand — in such a way that extra dimensions (as predicted by string theory) can facilitate the creation of a bubble of spacetime.
"Given that extra dimensions have not yet experimentally been shown to exist, and the idea that dark energy is an artifact of these extra dimensions is somehow related to these dimensions is clearly highly theoretical," Obousy told Discovery News, "however it provides us with an interesting perspective from which to examine the problem."
Although this method would theoretically allow a Alcubierre-like solution to traveling faster than the speed of light, vast amounts of energy would still be needed — the approximate mass-energy of Jupiter no less — but at least it's an improvement from the "all the energy in the Universe" solution.
Referring to White's work, Obousy continued: "The Jupiter calculation was purposefully created as an 'upper bound' to the problem, and I'm glad that the work performed by my colleagues has demonstrated ways to reduce the energy requirements down further."
The upshot is that the energy requirement for the warp drive is decreasing, albeit theoretically. With the help of quantum mechanics, we've seen a massive reduction in the amount of energy needed. And now, with White's tweak of warpship design, the energy has been reduced by many orders of magnitude. But the biggest news of all is that White and his NASA team are designing laboratory experiments that will, hopefully, form the foundations for a practical solution to building a warp drive.
"The findings I presented today change it from impractical to plausible and worth further investigation," White told SPACE.com's Clara Moskowitz at 100YSS. "The additional energy reduction realized by oscillating the bubble intensity is an interesting conjecture that we will enjoy looking at in the lab."
And as pointed out by Davis in the video below, there's no predicting when the next big physics breakthrough will happen, potentially aiding warp drive studies.
"Disruptive innovations are not predictable, they can pop up at any time between now and 200 years from now … we could have warp drive within our lifetime," Davis said. "We just can't predict when some genius is sitting somewhere and a lightbulb goes off over his head and he figures out an innovation which can overcome this problem of producing negative energy in large enough quantities."
So the next time someone tells you that the warp drive is "impossible," just tell them that real science is being applied to warping spacetime, NASA is even trying to replicate some of the warping effects with lasers in the lab and, besides, we never know what breakthroughs are just around the corner.
Image: Obousy's "warpship" (left). Credit: Richard Obousy Consulting and Alex Szames Antigravite. White's 'energy efficient' design (right) — note the "football" in the center of the ring. Credit: Harold White/NASA