NASA engages warp drive
Inspired by Star Trek, NASA scientists believe they can bend space-time and allow us to travel at many times the speed of light. Seriously. Cathal O'Connell reports on the most ambitious experiment ever.
On a floating tabletop inside a seismically isolated room deep within the sprawling Johnson Space Center, birthplace of the Apollo Moon missions, NASA scientists are performing one of the most ambitious experiments on the planet. Their aim is to use an extremely strong electric field to bend the fabric of space and time. The eventual application? Faster-than-light interstellar travel.
The story of NASA’s experiment is a strange case of science fiction inspiring real science. It begins in the early 1990s when Mexican theoretical physics PhD student and avid Star Trek fan, Miguel Alcubierre, sat down to watch an episode of the program. In the show, a technology called “warp drive” allowed ships to travel the yawning multi-light-year distances from star to star in the timescale of a prime-time episode. Alcubierre decided to use his understanding of general relativity to see how warp drive might work in the real world. Was faster-than-light travel really possible?
The problem Alcubierre had to sidestep was the “cosmic speed limit”, the speed of light. According to Einstein’s theory of special relativity, nothing can ever overtake a beam of light. But Alcubierre, inspired by the drive as described in Star Trek, spotted a loophole in the physics. Although everything in the universe is limited by the speed of light, the fabric of space and time itself, space-time, can expand or contract at any speed. That’s what happened just after the Big Bang, when the entire universe expanded at 1021 times the speed of light.
'While it sounds very sci-fi, the warp drive is theoretically possible,
by making space and time bend in a particular way.'
Alcubierre found that if space-time could be made to contract in front of the ship, and expand behind it, the ship would be propelled forward.
“While it sounds very sci-fi,” says Geraint Lewis, Professor of Astrophysics at the University of Sydney, “the warp drive is theoretically possible, by making space and time bend in a particular way. With this bending, a small bubble of unbent space-time can be propelled across the Universe at any speed you want.”
Sit your spacecraft in that bubble and you’re away.
Alcubierre published a landmark paper in 1994 describing solutions to Einstein’s equations that would allow for faster-than-light travel. His idea, now referred to as the “Alcubierre drive”, doesn’t violate special relativity because it is not the ship itself that is “moving” but the pocket of space-time it’s in. Harold White, head of NASA’s Eagleworks Laboratories where the experiment is being carried out, has likened it to an airport moving walkway. When standing on the walkway you can overtake people without much effort, because the belt beneath you is carrying you along.
When Alcubierre proposed his drive it was only a mathematical possibility, a novelty. An early attempt to calculate how much energy would be required to beat light-speed came out with impossible numbers, equivalent to the energy produced by the Sun over 10 billion years. But over the past two decades the idea has been refined, and with each improvement the energy requirements have been scaled down. It now needs the amount of energy equivalent to what the Sun gives out in less than one millionth of a second. Though way smaller than before, that is still a lot. It would take all of global human civilisation, running at 2008 levels, more than 130 years to generate this epic amount of energy. Obviously, any warp drive could only be achieved using advanced energy generation of a civilisation far into the future.
By 2011, NASA announced they were launching preliminary experiments to test its feasibility in the laboratory. The first step, according to White, is to create a “microscopic warp bubble” and measure it.
“We know nature can bend space-time,” says Lewis. Mass distorts space-time much like a bowling ball distorts the surface of a trampoline that it is sitting on, and energy can do it too if you have enough of it squeezed into a small enough space. The NASA experiment tries to do this by generating an extremely powerful electric field. To test the result they fire a laser through the field. Any space-time compression will shorten the distance travelled by the laser beam. So by comparing the distance travelled by the laser with the electric field on and the field off the team should be able to detect if their machine is warping space-time or not. “If it works,” says Lewis, it will be “the first baby steps in the direction of a warp drive.”
Preliminary results presented in late 2013 were inconclusive. White and his team are now working to increase the sensitivity of the instrument that measures the distance travelled by the laser beam. Whereas the previous set-up could theoretically detect a contraction of space of about 100 nanometres, the new one will be able to detect contractions of just 5 nanometres.
Even if White’s team succeeds, that would only indicate it could be possible to contract space-time in front of the spacecraft. The really tricky part, explains Lewis, is expanding space-time behind the craft – a feat that would require “negative energy”, or dark energy, to achieve. That’s something that we know exists – it explains why the universe is continuing to expand at an accelerating rate – but we have no idea how to produce it or shape it.
“Some think that malleable negative energy might be impossible, putting the proverbial spanner in the warp-drive works,” says Lewis. “But theoretical physics has not ruled this out.”
And, even with research at this very earliest stage, it is not so early that the NASA scientists aren’t already dreaming of what a warp drive-spacecraft might look like. So they’ve been working with Dutch digital artist Mark Rademaker on a concept design in the hope of inspiring young minds to consider science and technology careers. This month, Rademaker revealed his latest images of the ship.