Ask GR Anything: How do lightsabers work?

Ask GR Anything is a weekly Q&A column that answers questions submitted by readers (as well as questions we're particularly curious about ourselves). Got a burning question about games or the industry? Ask us in the comments below and you may just get it answered!

This week’s question comes not from a specific person, but from deep within the recesses of our collective minds. If you have a soul, then you’ve probably wondered, at some point, whether or not NASA will ever make good on all that money we’ve been sending them and bring home a lightsaber from one of their little trips. Or at the very least, somebody could make a crappy one just to show off on YouTube. Is it even possible? Given that it’s launch week for The Old Republic, we thought we’d try to find out.

The major force at work in a lightsaber is plasma, which is very real. To put it bluntly, plasma is the coolest thing on the planet. It’s not very common, but when it’s in the room, you’re going to know about it. What’s plasma? Plasma is lightning. Or to be more precise, it’s a highly excited form of gas. But it’s also not really gas. Confused? Good, that means you understand. Plasma is so weird that it’s earned a status as a completely different type of matter apart from solids, liquids and gases.

But this is good for us, because plasma can be used to melt crazy amounts of anything. There are things called arc furnaces that are used to melt huge amounts of scrap metal. Plasmas can have energy levels that take them to ridiculous temperatures. This has a couple different implications for lightsabers.

On the one hand, when we see Jedi/Sith slicing dudes up, that’s kinda realistic in a way. You don’t mess with plasma. But on the other hand, plasma isn’t something you can heat up in the handle of a flashlight (aka lightsaber).

“It still takes a lot of energy to melt things, so this energy must first be put into the plasma before the plasma can melt anything,” said a representative of the Princeton Plasma Physics Laboratory when we emailed asking lightsaber questions. So it’s fairly unrealistic to think that a plasma sword that large could be sustainably powered for a stretch of time far from a power source. Ultra-nerds estimate the power usage at several mega-watt hours per use. But then again, it’s Star Wars. They’ve got Wookiees; anything is possible.

We actually have handheld plasma devices that are hooked up to very large power supplies. They’re called plasma torches, but don’t get excited. Plasma torches require contact with the metal you’re working with in order to form. But when they do light up…they burn at a mind-blowing 45,000 degrees. For those of you keeping score at home, that’s about four times hotter than the surface of the sun. Like we said, don’t mess with plasma.

The lightsaber problem was dissected some time ago by an engineer at General Electric, who broke down the machine and tried to figure out a way to make one work. He also took the time to rip apart George Lucas’ insane vision for how a lightsaber might work. Lightsabers have a focusing crystal (one of the most important parts) which focuses the plasma into a stable beam. But as the GE engineer points out, that doesn’t make sense on even the most basic level.

“There are […] no crystals that can ‘direct’ a plasma. In fact, a plasma ‘being directed’ by a crystal lens doesn’t make any physical sense anyway. A plasma is really just an ionized gas.” What he’s saying is that you can’t focus plasma through a crystal any more than you can focus the wind through your glasses. Gases don’t pass through solids.

That said, this guy (whose name is Matt Gluesnkamp, if you care) also believes that a laser-based lightsaber could be possible. Although it’d be more akin to No More Heroes than Star Wars.

“An electrical arc can have wild shifts in direction, and it can hardly be controlled without being surrounded by magnets,” Gluesnkamp said. “A laser will go in a straight line, but of course it doesn’t stop. A laser-based lightsaber would require a block or a couple of mirrors floating in midair, moving in sync with the hilt – which is of course largely impossible.”

So no, you can’t have a lightsaber. But you can buy a plasma torch online for a little over a thousand dollars. They’re not going to work like the industrial ones, but if you absolutely need to melt through some capital ship blast doors, then that’s probably your best bet.

Submit your own questions in the comments (or Tweet them to @sciencegroen) and we may tackle them for a future Ask GR Anything.


  • brizzie - December 29, 2011 3:31 p.m.

    The Jedi had been established for around 11,000 years before even the most basic form of lightsaber was created and they had been far more advanced than us at the start of their order
  • mowww25 - December 28, 2011 10:30 a.m.

    Theres an episode of Nova where they explain how they could make a real lightsaber xD
  • LordAugastus - December 27, 2011 11:01 p.m.

    I had always wondered what made the lightsaber up as a child too. After a while and little understanding of the sci-fi inner-workings of the saber i could not figure it out(I allways assumed it was a laser :S ). With my ongoing knowledge of the sciences i made different theories but never one that fitted the star wars version. I just stopped thinking about it, After a while i assumed that its just a movie/novel idea. A real life application of a similar technology using either electricity or laser, was to have a small pole running the length of the blade and having the anode on the end/tip allowing for movement as described above, i saw it in a different MMO as a lightning sword. Assuming the future advancement in nano-carbon tubing i think it is possible to have a hair thick pole extending the length of the saber to catch the laser light/electricity? .
  • Andrew Groen - December 28, 2011 10:55 a.m.

    I'm labeling your post: "Reason #974364897 Why I Love GR Readers."
  • Andrew Groen - December 27, 2011 3:31 p.m.

    Forever isn't long enough.
  • EpicBacon1073 - December 24, 2011 10:11 p.m.

    Gdar, i need a good mmo. Ive never really gotten that deep into one, but for whatever reason im craving one right about now. All the mmos ive tried so far were either not fun, just addictive, or relied to heaviliy on grinding. I'd prefer it to be free to play, but if you really think it goes the extra mile and get me in to mmos, then id be okay with paid.
  • Andrew Groen - December 26, 2011 5:44 p.m.

    I'm personally a big fan of Lord of the Rings Online which is a great F2P option. My favorite paid MMO right now is Rift, though I haven't tried SWTOR. On the horizon though, Firefall looks like it's going to blow just about everything else away. I've played it a few times at trade shows and it's loads of fun.
  • Dadyo238 - December 23, 2011 8:55 p.m.

  • Person5 - December 23, 2011 9:29 a.m.

    I'm pretty sure that in the movies the way they get the beam to stop is by stopping it with the Force, so the only TRUE way we'll get a lightsaber is if we as a species realize within ourselves how to tap into the Force
  • frankenfurter - December 24, 2011 7:23 a.m.

    General Grievous has a few lightsabers, he's not got any force powers. Who knows what people will be able to invent and produce in a thousand years. I also think scientists are extremely short sighted when saying somethings impossible. Beside's its a film, a wish scientists and engineers would find better things to do with their time than poo-poo movies.
  • Andrew Groen - December 26, 2011 5:50 p.m.

    Scientists generally aren't short-sighted. Most of the ones I've talked to (which is a lot) over the years for my articles are very open to the idea that their understanding of their field could change wildly if a huge discovery is made. You just never see that on TV because TV networks like to portray certitude and brilliance. Viewers don't like wishy-washy intelligent scientists. They like rockstars who never doubt themselves and fly in the face of convention. So that's how they portray Einstein, Feynman, Hawking etc. Also the show would suck if we had to listen to every scientist say "but who knows, everything could change tomorrow for all I know."
  • ItBurnsWhenIWii - December 22, 2011 11:12 p.m.

    Yo GR, what is the meaning of life?
  • - December 23, 2011 1:02 a.m.

    Cash money.
  • AGENTJORRRG - December 22, 2011 9:01 p.m.

    If you had a lightsabre and pointed the business end at the floor and let it drop, would it fall all the way to the centre of the Earth?
  • - December 23, 2011 1:01 a.m.

    Haha Good question. But I imagine that the handle would get wedged inside the hole after about 1.5 feet.
  • AGENTJORRRG - December 23, 2011 12:53 p.m.

    Good answer...Alright, what if you javelin threw it at the floor, or fired it out of a cannon directly downwards, then?
  • Andrew Groen - December 28, 2011 11:30 a.m.

    Haha Alright, I'll bite. I think what you mean is "what if it didn't get stuck?" Then I suppose the answer is that it'd keep falling until the heat of the Earth caused enough damage to the handle that it malfunctioned...then it'd get stuck again.
  • TheFabricOfTime - December 22, 2011 1:21 p.m.

    I have a good question... how many lightbulbs would it take to replace all of the torches in all of Bowser's castles? Not just one game either... ALL THE GAMES.
  • - December 22, 2011 2:13 p.m.

    Haha I'm not sure what you mean. Does that mean the same as "How many torches are there?" How many lightbulbs equal a torch?
  • inkyspot - December 22, 2011 4:45 a.m.

    I had figured this out as a kid (Not in the depths of detail you guys did, thanks for that). I was wondering how can they make light just form and stop instead of just continuing. I was trying in my head to make it as real as possible (Who knows what the future could bring? Could cavemen even imagine the Internet or the concept of a plane?) I was thinking that some sort of holding rod would extend from the base of the light saber and that would be heated with whatever energy to the point where it was super hot (This would explain why this glowing light stops IMO) Please understand I thought of this as a child. The extendable rod will then retract when the Jedi releases the weapon. Also the weapon (Light saber) is sort of DNA specific so only that specific Jedi the Saber was constructed for could use it. I suppose if you put anything far enough in the future you can say it may be possible on some level, Since we really don't know. Here's my question. How far in the future is Star Wars and does earth exist in that universe (Since humans do)?

Showing 1-20 of 54 comments

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