A still photo of Mark Hamill as Luke Skywalker and Bob Anderson as Darth Vader in "Star Wars: Episode V, The Empire Strikes Back" (1980)Lucasfilm

The lightsaber is an intimate weapon. Its neon glow may be visible from afar, but the lightsaber is designed for face-to-face combat. It is personal, precise, and deliberate—emitting no haphazard pew-pew-pewing, but instead a reassuring, almost meditative hummmmmm.

That sound was invented in a mixture of serendipity, imagination, and mundanity. “I could kind of hear the sound in my head, of lightsabers,” said Ben Burtt, the sound designer who created the distinctive pitch, in an interview for a Star Wars video extra. “I think maybe somewhere in my subconscious.”

At the time, Burtt, who had majored in physics during college, was a graduate student at the University of Southern California’s School of Cinema-Television. He helped operate a projection booth at the school that used ancient Simplex projectors, the kind that used to whir and murmur in old movie houses. “And they had an interlock motor which connected them to the system, which, when they just sat there and idled, made a wonderful humming sound,” Burtt said. “It would slowly change in pitch, and it would beat against another motor—there were two motors—and they would harmonize with each other.”

That pleasant white noise became the foundation for what the lightsaber would sound like. “It was just a humming sound,” Burtt said. “What was missing was kind of a buzzy, sparkling sound, the scintillating element which I was looking for. And that I found it one day by accident.”

On that day, Burtt was recording something, and crossed the room with his microphone still turned on. When he passed by a television set that was on but with its volume all the way down, the microphone let out a whine. “An unusual hum,” Burtt said. “It picked up a transmission from the television set and a signal was induced into its sound-reproducing mechanism. That was a great buzz, actually. So I took that buzz and recorded it and combined it with the projector motor sound and that 50-50 combination of those two sounds became the basic lightsaber tone.”

From there, all Burtt needed was a sense of motion, the thrumming and slashing of battle. He achieved that by taking a microphone and waving it through the air next to the speaker as the foundational lightsaber sound was playing. “What happens when you do that, by recording with a moving microphone, is you get a Doppler shift, you get a pitch shift in the sound, and therefore you can produce a very authentic facsimilie of a moving sound."

The onscreen look of the lightsaber was, of course, at least as important as the noise it made. The original lightsaber handles were made from pieces of old flashgun battery packs, from the kind of camera where you had to hold up the flash separately. In the first films, a technique called rotoscoping made the lightsabers glow; today they’re digitized.

Mesmerizing sound and a three-foot blade of colorful light make the lightsaber distinct and otherworldly; but how the weapon is wielded is what makes it classic. Epic battles are fought in the tradition of world-class swordsmen. For an object so influential in the realm of fictional technology, it is the lightsaber’s real-world elegance that makes it memorable.

Unlike a blast gun—also featured in the Star Wars universe—the lightsaber is a defensive weapon, one that’s meant to be used as a last resort. It requires skill, a sense of tradition, and that most elusive of power source: The Force. (Obviously, lightsabers aren’t exclusively used in self-defense. Villains wield them aggressively, hacking through the air with lightsabers that appear more like battle axes than artful swords in their hands.) Preparing for a lightsaber duel is like learning intricate dance steps, according to Ewan McGregor, who played a young Obi-Wan Kenobi, the Jedi master, in the more recent films. “Every stroke is choreographed,” he told the audience at a New York Times-hosted event in 2012.

Lightsabers are fantastical, but they may be technologically possible. They’re lasers, after all. (Though “lightsaber” is far more romantic a name than “lazer sword,” which Star Wars creator George Lucas used in early scripts.) Outside of the Star Wars universe, lightsabers would be powered by plasma instead of The Force.

“You would have a sword that ejects a long tube, and the tube has holes in it, which emits plasma,” the theoretical physicist Michio Kaku told the Times in 2008. “They could be heated to enormous temperatures, and in some sense, they would be able to fry any object they came close to.”

The problem, Kaku points out, is the portability factor. In order for a lightsaber to be totable, an essential characteristic for traipsing around the galaxy, it would need a power pack. “We see pictures of lasers blasting through objects, and we can do that now,” he said. “But you have a nuclear power plant behind that laser.” And to enter into a lightsaber duel only when you have a power plant right there would be, he says, “impractical.”

Some fans argue lightsabers are impractical anyway. Why do Jedis often risk hand-to-hand combat with horrifying enemies when they could theoretically use blasters, hull-crackers, sky torches, phasers, or any number of other destructive and powerful weapons from a distance? Because a lightsaber is “not as clumsy or random as a blaster,” Obi-Wan tells Luke Skywalker in the original film.

The lightsaber may be unusual in the Star Wars universe, preferred only by elite Jedis and Siths, but the weapon is ubiquitous in our world. Few other pieces of imagined technology even approach its influence. In 1977, one toy company sold out of gift certificates promising lightsaber toys that were still being manufactured. There are, at least, dozens of variations of lightsabers that can be purchased, including inflatable party-favor lightsabers, cheap Halloween-costume versions made of hard plastic, hand-crafted wooden lightsabers, and delicate replicas that glow with LED lights and cost hundreds of dollars. There are, for intellectual-property purposes, countless Forcebeams and LaserSabers and Force Sabers of Light.

One of the parlor tricks among early adopters of the iPhone was a lightsaber app, complete with a version of the weapon’s distinctive hum that would change pitch as the phone moved through the air. The lightsaber plays a significant role in early Internet memedom, too. The “Star Wars Kid” video, featuring a young man swinging a golf-ball retriever as though it's a double-sided lightsaber, has been remixed endlessly and parodied across pop culture since it first went viral in 2002. In 2008, the lightsaber that Luke Skywalker slashed through the air in “The Empire Strikes Back” sold at auction for $240,000. Today, there are gyms, dance studios, and academies that teach lightsaber choreography and dueling.

And though the lightsaber has several clear predecessors in science fiction pre-Star Wars, the lightsaber is iconic because of its originality: That strange hum, the steady fairy-like glow, the weapon’s ability to clock The Force. With lightsabers, the message is that a machine can be both fearsome and beautiful, simultaneously subtle and spectacular—but that technology is ultimately nothing without the will of the creature who powers it. “An elegant weapon,” as Obi-Wan says, “for a more civilized age.”

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