Science & Technology

We Might Actually Be Able to Make a Lightsaber

Pretty much every science fiction series worth its salt has laser guns. Most of them have lightspeed travel, intelligent robots, and forcefields, too. But there's only one that's got glowing laser swords that can cut through anything. Now that "The Last Jedi" is about to hit the theaters, we got to wondering if you could make a lightsaber in real life.

An Elegant Weapon for a More Civilized Age

So, what is a lightsaber? Is it a laser beam contained in a sword-shaped sheath? A spout of burning plasma? A blade of nebulously defined "energy"? The answer is ... inconsistent. StarWars.com doesn't say much about how the actual "saber" part works, and while George Lucas briefly referred to the weapons as "laser swords," Wookiepedia specifically calls them a "plasma blade powered by a kyber crystal." (One thing we can say for certain: kyber crystals are not real.) Now, we don't want to break any nerd hearts, but the laser version of the weapon will almost certainly never be a reality — it would basically be impossible to keep the laser from just shooting off forever instead of staying contained in a four-foot blade shape.

So it's probably safe to say that smart money is on the plasma theory. And on that count, we actually have some good-ish news. Just as a refresher, plasma is the fourth state of matter — with enough heat, solids become liquids, liquids become gases, and gases become plasmas, meaning the atoms are stripped of their electrons.

Writing for Scientific American, Fermilab senior scientist Don Lincoln described exactly how a plasma-filled lightsaber could work. "Because a plasma is electrically conductive, it can convey a large electrical current to the target material, heating it up and melting it. [...] Plasmas, being composed of charged particles (some with very high velocities), can be manipulated by magnetic fields."

In other words, if you were able to generate a tube-shaped magnetic field in addition to the high-energy plasma, you'd be left with a sword capable of cutting through almost anything. There's just one final problem: you wouldn't be able to duel with them. Even with the magnetic fields, the blades would pass right through each other. So maybe we're back to the drawing board.

There's really just one more chance — a new hope, if you will. In 2013, physicists from Harvard and MIT were able to create a never-before-seen form of matter they called "photonic molecules" by launching the photons through a cloud of cooled rubidium atoms, prompting them to group together in order to move through the cloud. In other words, they created little globules of light that could actually interact instead of harmlessly passing through one another. That means that if you were able to make swords out of these molecules, those swords would bounce off each other. There's not really any plan to try to do such a thing, though — and anyway, there's no guarantee that they would make those cool vwoom noises.

Do or Do Not, There Is No Try

This is all very theoretical. Which is to say, it's probably not ever going to actually happen. But there are some heroes out there doing their best to bring bright-green energy blades into the real world. One example is the Flash Torch, a flashlight so strong it can literally start fires using light alone ... but it doesn't really scratch the "saber" itch. Then there are these Laser Sabers, which certainly look the part but are more like highly advanced props than anything else.

For our money, the person to come the closest to building an actual lightsaber is Alan Pan, an incredibly creative engineer who competed on the show "Mythbusters: The Search." (You might also remember when he made a version of Thor's hammer that only he could lift). His 'saber is actually more of a concentrated chemical flamethrower. It casts a green flame in a straight line, and it works surprisingly well at both looking like a lightsaber and cutting stormtroopers down to size — provided those stormtroopers are cardboard cutouts. Still, you definitely don't want to be standing on the wrong end of this thing. Now, if only we could get this "Force" thing figured out.

For more real-life science behind this sci-fi franchise, check out "The Physics of Star Wars: The Science Behind a Galaxy Far, Far Away" by Patrick Johnson. The audiobook is free with a trial of Audible. If you make a purchase through that link, Curiosity will get a share of the sales, which helps support the work that we do. 

How to Make a Real Lightsaber

Written by Reuben Westmaas December 7, 2017