A new paper proposes a fully physically realized model for warp drive.
This builds on an existing model that requires negative energy—an impossibility.
The new model is exciting, but warp speed is still probably decades or centuries away.
In a surprising new paper, scientists say they’ve nailed down a physical model for a warp drive, which flies in the face of what we’ve long thought about the crazy concept of warp speed travel: that it requires exotic, negative forces.
To best understand what the breakthrough means, you’ll need a quick crash course on the far-out idea of traveling through folded space.
The colloquial term “warp drive” comes from science fiction, most famously Star Trek. The faster-than-light warp drive of the Federation works by colliding matter and antimatter and converting the explosive energy to propulsion. Star Trek suggests that this extraordinary power alone pushes the ship at faster-than-light speeds.
Scientists have been studying and theorizing about faster-than-light space travel for decades. One major reason for our interest is pure pragmatism: without warp drive, we’re probably never making it to a neighboring star system. The closest such trip is still four years long at light speed.
Our current understanding of warp speed dates back to 1994, when a now-iconic theoretical physicist named Miguel Alcubierre first proposed what we’ve called the Alcubierre drive ever since.
The Alcubierre drive conforms to Einstein’s theory of general relativity to achieve superluminal travel. “By a purely local expansion of spacetime behind the spaceship and an opposite contraction in front of it,” Alcubierre wrote in his paper’s abstract, “motion faster than the speed of light as seen by observers outside the disturbed region is possible.”
Essentially, an Alcubierre drive would expend a tremendous amount of energy—likely more than what’s available within the universe—to contract and twist space-time in front of it and create a bubble. Inside that bubble would be an inertial reference frame where explorers would feel no proper acceleration. The rules of physics would still apply within the bubble, but the ship would be localized outside of space.
It might help to think of an Alcubierre drive like the classic “tablecloth and dishes” party trick: The spaceship sits atop the tablecloth of spacetime, the drive pulls the fabric around it, and the ship is situated in a new place relative to the fabric.
Alcubierre describes spacetime expanding on one side of the ship and contracting on the other, thanks to that enormous amount of energy and a requisite amount of exotic matter—in this case, negative energy.
Is NASA Working On a Warp Drive?
Some scientists have criticized the Alcubierre drive, however, because it requires too much mass and negative energy for humans to ever seriously construct a warp-based propulsion system. NASA has been trying to build a physical warp drive through Eagleworks Laboratories for most of the last decade, but hasn’t yet made any significant strides.
This brings us to the new study, which scientists in the Advanced Propulsion Laboratory (APL) at Applied Physics just published in the peer-reviewed journal Classical and Quantum Gravity. In the report, the APL team unveils the world’s first model for a physical warp drive—one that doesn’t require negative energy.
The study is understandably pretty thick (read the whole thing here), but here’s the gist of the model: Where the existing paradigm uses negative energy—exotic matter that doesn’t exist and can’t be generated within our current understanding of the universe—this new concept uses floating bubbles of spacetime rather than floating ships in spacetime.
The EmDrive Just Won’t Die
The physical model uses almost none of the negative energy and capitalizes on the idea that spacetime bubbles can behave almost however they like. And, the APL scientists say, this isn’t even the only other way warp speed could work. Making a model that’s at least physically comprehensible is a big step.
Plus, Alcubierre himself has endorsed the new model, which is like having Albert Einstein show up to your introductory physics class.
Of course, there’s one gigantic caveat here: The concept in this paper is still in the “far future” zone of possibility, made of ideas that scientists still don’t know how to construct in any sense.
“While the mass requirements needed for such modifications are still enormous at present,” the APL scientists write, “our work suggests a method of constructing such objects based on fully understood laws of physics.”
But while a physical drive may not be a reality today, tomorrow, or even a century from now—let’s hope it’s not that long—with this exciting new model, warp speed travel is now a lot more likely in a much shorter timespan than we previously thought.