Humans shed a lot of blood, sweat and tears in search of the almighty loophole. From sweet tax dodges to life-extending gene hacks, there’s nothing like finding an exploitable weakness in an intensely complicated system.
But is it possible to find a loophole in the universal speed limit? Can we skirt Einstein’s theory of special relativity and travel faster than a beam of light?
“As an object approaches the speed of light, all sorts of interesting things happen,” says theoretical physicist Richard Obousy. “For example, time dilation occurs and an object’s mass increases. As you reach the speed of light, relativity calculations indicate that an object’s mass becomes infinite.”
Plug in the numbers, Obousy says, and you face some staggering fuel costs. To accelerate an object to the speed of light, you’d need nothing short of an infinite amount of energy. There has to be a better way, right?
Cosmic wormholes might open a doorway to the other side of the galaxy, but scientists continue to ponder the rich possibilities of another loophole in relativity: the warp drive.
“Instead of moving through space, you actually move the fabric of space itself,” Obousy says. “A hypothetical spacecraft would remain stationary inside a bubble of mutually expanding and contracting space-time. So, whereas an object moving through space is restricted by the rules of relativity, there are no such rules and restrictions regarding space itself.”
How’s that for a loophole? From a theoretical standpoint, the universal speed limit only applies to things moving through space, not space itself. Of course, it helps to lay a little evidence on the table.
“We indeed believe that space-time expanded at many, many times the speed of light during the inflationary period, which occurred in the first fraction of a second after the big bang,” Obousy said.
In a very broad sense, the question of warp speed feasibility comes down to this: Given sufficiently advanced technology, would it be possible to recreate this space-time expansion and exploit it for interstellar locomotion?
Make no mistake: Warp drive technology is highly speculative. Astrophysicists such as Obousy, Miguel Alcubierre and Kip Thorne have explored the underpinning theories in various papers, but it remains far-future technology at best.
Depending on whom you ask, the fuel costs alone are truly mind-boggling. Early theories required more energy than you’d find in the entire universe. Later papers scaled this down to merely all the energy in a single galaxy, effectively downgrading warp drives to a type III Kardashev civilization technology.
The latest versions of Obousy’s own warp speed models scale down energy demands even further, requiring the kind of power output you’d get from converting Jupiter’s mass into pure energy.
“So the problem went from being impossible to just very, very, very, very, very difficult,” Obousy says.
Given the highly theoretical nature of warp speed travel, safety issues usually take a backseat to fundamental questions about its feasibility. Still, John Hopkins University radiology professor William Edelstein made science headlines in 2010 with his concerns about the radiation risks of faster-than-light travel.
Edelstein’s concerns mostly boil down to the amount of interstellar hydrogen in the universe. These atoms permeate even seemingly empty reaches of space. While the universe’s density of interstellar hydrogen is fairly low, a fast-moving starship would blow through them like a truck grille through bugs.
“There are about two atoms per cubic centimeter probably in the galaxy,” Edelstein says. “There’s hardly anything there, but nevertheless it’s enough to be dangerous and in fact fatally dangerous. So when you’re going fast, the hydrogen atoms come at the ship with high energy, penetrate the ship and irradiate the occupants.”
Furthermore, these atoms would collide with a high-speed spaceship with incredible energy, a situation Edelstein equates with standing in front of a particle beam in the Large Hadron Collider.
“Six sieverts of radiation is fatal for people,” Edelstein says, “but [at a speed of .99 the speed of light] you’d get 61 sieverts in one second. You’re going to last a fraction of a second.”
So are hydrogen atoms unavoidable space mines? Would a real-life Capt. Kirk eat an infinite amount of radiation every time someone engaged the warp drive?
Edelstein doesn’t believe efficient shielding is possible, but Richard Obousy believes metamaterials or two-dimensional sheets of nanotech graphene might provide sufficient protection, assuming that moving via a warp bubble wouldn’t skirt the issue entirely.
“For the warp drive, a space vehicle is stationary inside a bubble of contracting/expanding space-time,” Obousy says. “There are quantum back-reactions that need to be taken into consideration, but hydrogen atoms would do no more damage than they do to, say, the space shuttle.”
For the foreseeable future, scientists will continue to ponder what’s possible and what’s impossible when it comes to the dream of warp speed travel.