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The Science of Lightsabers

sethmad writes "As everyone who's ever passed the GRE knows, there are two major hypothetical operational problems with Star Wars lightsabers. More accurately I should say there were two problems, because I solved both of them."

32 of 232 comments (clear)

  1. What are your patent numbers? by perpenso · · Score: 3, Funny

    More accurately I should say there were two problems, because I solved both of them.

    What are your patent numbers? :-)

    1. Re:What are your patent numbers? by Hognoxious · · Score: 3, Funny

      And how many parsecs until they expire?

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    2. Re:What are your patent numbers? by jmd_akbar · · Score: 3, Funny

      And how many parsecs until they expire?

      And here I thought Parsec was a unit of distance...

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    3. Re:What are your patent numbers? by stubob · · Score: 2

      Unfortunately, there's prior art from a long, long time ago in a galaxy far, far away.

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  2. The British.... by Anonymous Coward · · Score: 3, Informative

    We would call them Torches you idiot!

  3. That still has the magnet problem... by Zakabog · · Score: 3, Insightful

    If you're using a magnetic field to control the plasma then any magnet can still interfere with the light saber. For some reason I was expecting a much more technical article than 'its got a metal rod in the center, tada!'

    1. Re:That still has the magnet problem... by larry+bagina · · Score: 5, Insightful

      Yeah, this was stupid and pointless, even by idle standards. Maybe /. needs to add a retarded section.

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    2. Re:That still has the magnet problem... by dmgxmichael · · Score: 2

      heh heh yup. I also thought that the largest problem with a lightsaber being plasma is that to cut as efficiently as portrayed it would roast anyone within a football field of it. Little problem called convection and the laws of thermodynamics.

    3. Re:That still has the magnet problem... by Kell+Bengal · · Score: 4, Interesting

      When I was younger (and nerdier) I once proposed a similar but more sensible version using in-universe technology that was well understood by Starwars fans: force fields. Obviously, starships have shields that keep asteroids, debris, weapons and projectiles from damaging them. Similarly, speeders and various devices apply forces at a distance to hover and float. Why can't this technology be used to harness a plasma field as a cutting device?

      It stood to reason that the interaction of these repelling, focussing fields would result in the spark and fizzle of lightsabres clashing, as tiny amounts of plasma escaped. Likewise, the interactions would prevent the blades from passing through each other and also account for occasional 'sabre lock' where two blades are periodically joined and must be separated.

      As I said, I was younger and nerdier back then.

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    4. Re:That still has the magnet problem... by XanC · · Score: 2

      Don't say "don't say retarded".

    5. Re:That still has the magnet problem... by oldmac31310 · · Score: 2

      So, you're saying /. needs a 'gay' section? Fair enough.

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    6. Re:That still has the magnet problem... by sshirley · · Score: 2

      and gay

    7. Re:That still has the magnet problem... by PitaBred · · Score: 2

      You were just younger. The fact that you're bragging about it now means you're still just as nerdy, if not more so ;)

    8. Re:That still has the magnet problem... by DavidTC · · Score: 5, Interesting

      The biggest problem with lightsabers isn't even the science of them.

      It's that they're insane weapons.

      Look, if you have something that can cut through anything, you shoot it at people. Imagine a dual-lightsaber that's 3 inches long, operates for five seconds, and is shot, spinning, at people. Hell, forget shot, you could put a release timer on them and throw them at people, having them spring into action a quarter second after release.

      Perhaps there could be spinning death frisbees. Can you curve a light blade around the edge? ;)

      Or perhaps you could just fire the 'blade' itself, leave the generator behind. But I think that's disallowed under the 'rules' of lightsabers, which says the light blade goes out and then comes back, which also has the benefit of saying that lightsabers don't use power unless they're actually cutting something, otherwise, they're 100% efficient. (Except that they're always cutting the air, hence the hum, so always use a tiny amount of power.)

      All I really know is waving it around near your body is a good way to lose parts of your body.

      But, even stupider, there appears to be no reason you can't slide your blade down the other guy's blade and cut off his fingers. Unlike traditional swords, there's no guard, nor can there be one.

      Likewise, as they're weightless, there's no reason to not have very long ones. Lightpikes, you just aim them at the enemy, push a button, and the blade extends twenty feet out, straight through their torso. You jerk it upward, slicing them in half. Then cut off the blade and go to the next guy, or just wave it back in forth in an arch if they're all coming at once. (Hell, you wouldn't even need to be a Jedi to safely use one of those!)

      Granted, you couldn't block blaster fire with one, but there's no reason you couldn't have short and long setting, or at least a duel-weapon with a short and long side.

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    9. Re:That still has the magnet problem... by sakdoctor · · Score: 4, Funny
  4. Why did this get posted? by ceoyoyo · · Score: 5, Insightful

    Come on. Half the comments on this story are probably going to be better than this dork's.

    A light saber that used plasma would likely be hot. Hot enough that holding it would get very uncomfortable, magnetic field or no. And if the magnetic field is confining it, how does it get through the porous metal? Without destroying the metal? Where does the plasma come from if it's constantly leaking out? Why do lightsabers require focusing gems? How does a light saber deflect blaster and laser hits that would otherwise melt metal? How can lightsabers be an ancient weapon and the guy who designed them is still living on some planet somewhere?

    1. Re:Why did this get posted? by TemporalBeing · · Score: 2

      A light saber that used plasma would likely be hot. Hot enough that holding it would get very uncomfortable, magnetic field or no.

      Valid point. Though temperature is highly dependent on the substance used to make the plasma and the amount of plasma to start with. And since we're in this fictional world - the handle could have a built-in cooling method that abates the temperature as it gets closer to the holder - that could even be part of the power system used to heat the plasma.

      And if the magnetic field is confining it, how does it get through the porous metal? Without destroying the metal?

      The magnetic field would need to exist outside the porous metal by at least a few millimeters to as much as a couple inches. Whether or not the metal is destroyed depends on the metal and its melting point. Thereby the metal used would have to have a melting point considerably higher than the temperature of the plasma.

      Where does the plasma come from if it's constantly leaking out?

      The magnetic field contains the plasma so while it is leaking out of the porous metal, it gets recycled back in later on. Thereby, no loss of substance. Perhaps the hottest parts are extruded from the tip and fall back towards the handle as they cool, following the flow of the magnetic field.

      Why do lightsabers require focusing gems?

      Perhaps to keep the temperature of the plasma just right? Perhaps to run the power source?

      How does a light saber deflect blaster and laser hits that would otherwise melt metal?

      Magnetic fields are well known for changing the direction of light, even subtly. Of course, aside from the fact that the field/plasma would burn/melt a bullet - it wouldn't be much help in all cases.

      How can lightsabers be an ancient weapon and the guy who designed them is still living on some planet somewhere?

      Depends on your definition of ancient. The guy could be from a race that lives for a very, very long time. Yoda was nearly 1000 when he died in episode 5; and the Palpatine was at least as old as Yoda from the back story given - yet didn't look it until the end of Episode 3 when he had to draw from everything built up in him to fight off the Jedi as opposed to using it to maintain his age. So anything is possible - especially in such a fictional universe.

      Of course, this also means that the magnetic field would have to be finely tuned for the materials used (perhaps accounting for the differences in color between different light sabers), and it would also suffer from magnetic interference from numerous sources - some of which would be fatal to its use or longevity as a weapon.

      And, of course, there is the simpler solution which applies only in the fictional Star Wars Universe - the light saber itself is not actually a laser/light/plasma blade but made up of the force (in a physical, more concentrated form of the midoclorians) as manipulated by its wielder, thereby requiring the ability to manipulate the force to use it (consistent with Star Wars AFAIK). Stronger users of the force could therefore have longer blades if desired, and the focusing gem is just a focal point for the wielder. In other words, the light saber is just a smaller, more useful version of the lightning emitted by powerful Jedi/Sithe that can be used with less skill in the force by those that have been properly trained. Sadly, this does nothing for science in the real world.

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    2. Re:Why did this get posted? by kimvette · · Score: 2

      And, of course, there is the simpler solution which applies only in the fictional Star Wars Universe - the light saber itself is not actually a laser/light/plasma blade but made up of the force (in a physical, more concentrated form of the midoclorians) as manipulated by its wielder, thereby requiring the ability to manipulate the force to use it (consistent with Star Wars AFAIK). Stronger users of the force could therefore have longer blades if desired, and the focusing gem is just a focal point for the wielder. In other words, the light saber is just a smaller, more useful version of the lightning emitted by powerful Jedi/Sithe that can be used with less skill in the force by those that have been properly trained. Sadly, this does nothing for science in the real world.

      And yet, Han Solo, an athiest analog in the Star Wars universe who refused to believe in the force, was able to use a light saber to cut open a tauntaun.

      What happened to just enjoying a fantasy story at face value and not geeking out over the petty little details?

      (I'm so ashamed I remember not only little details of the plot but creature names as well!)

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    3. Re:Why did this get posted? by AmiMoJo · · Score: 2

      What happened to just enjoying a fantasy story at face value and not geeking out over the petty little details?

      Frasier: Think about it, Niles. What's the one thing better than an exquisite meal? An exquisite meal with one tiny flaw we can pick at all night.

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  5. Um... What's a... by camperdave · · Score: 3, Funny

    What's a GRE and why would passing one allow you to know hypothetical problems with Star Wars tech. I passed a truck full of pigs on the 401 and the only thing I learned is "stay upwind of the pig trucks"

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    1. Re:Um... What's a... by Eric+Sharkey · · Score: 2
  6. Re:Already Been Done by swanzilla · · Score: 2

    If said guy used the extend-able metal tube to drink his own urine, chances are good it was Bear Grylls.

  7. Copied solution or not? by mwvdlee · · Score: 2

    I'd like to say this was copied from the TV series in which Dr. Michio Kaku presented the exact same "solutions" to those two lightsaber problems (http://www.youtube.com/watch?v=xSNubaa7n9o), but in the same series he also discusses a time travel machine, so who know; he may have copied the ideas from this kid.

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  8. Old idea, doesn't work. by SanityInAnarchy · · Score: 5, Interesting

    I don't remember where I've heard this before, but I've definitely heard it. But there are some very large problems you haven't solved.

    First, this is still going to require a large amount of energy. Where does that come from? And if you've got something superheated into a plasma, how do you keep the metal from melting?

    Second, as others have pointed out, you haven't actually solved the magnetic-field problem. Basically, any Jedi could have his lightsaber entirely disabled, or even turned back on him, by inducing a magnetic field on the room he's in.

    Third, it doesn't explain the part where lightsabers are incredibly difficult to wield, due to weird gyroscopic effects, such that only someone with force-sensitive reflexes should be able to wield them properly. Ok, Han Solo can cut open a tauntaun, but that's a pretty crude motion -- try to swing it around, and if you're not careful, you could end up cutting yourself as easily as your opponent.

    Fourth (!), what are blaster bolts, and how does a lightsaber deflect them? It makes very little sense to suppose that a blaster bolt is just some plasma wrapped around a tube in the same way -- that seems awfully complicated compared to alternatives like just firing the plasma as a projectile -- and then, why would they bounce off force fields the way they do, as if they were somehow slowly-moving laser light?

    Finally, how do you explain the phenomena in Episode 1... Alright, maybe you want to pretend that didn't exist, but this phenomena is fairly commonly observed and generally accepted as something that it'd be reasonable for a lightsaber to do. Anyway, what about the point where Qui-Gon and Obi-Wan are trying to break into a room by slowly melting the blast door with their lightsabers? I suppose the metal rod could be collapsing, but then I'd expect that when you pull it out, it'll have to slowly extend again -- and it also suggests that lightsabers would collapse entirely too easily. If they're made of light, this makes much more sense, but then we have all the same problems as light.

    So, cool idea, but let's just accept that Star Wars is science fantasy. It's enjoyable science fantasy, and there's no shame in wanting to be a jedi, but you'll never have a lightsaber. (Also, there's no Santa. Sorry.)

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  9. Re:Noise by The+Grim+Reefer2 · · Score: 2

    He hasn't solved the most difficult problem, though: the noise. Normally, a light saber like that would be completely silent. How do you let it make those whooshing sounds?

    The same way you did with a stick when you were a kid. Make "Vruu Vruu" noises while swinging it. ;-)

  10. Re:Noise by michelcolman · · Score: 2

    I bet there's an app for that already :-)

  11. Re:Noise by GameboyRMH · · Score: 2

    Anything with a big 'ol vibrating transformer in it will make a similar noise. My dad has a power conditioner on his computer that makes a similar noise if you pick it up and swing it around.

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  12. Bah, everyone knows they are made of.. by shadowrat · · Score: 2

    midichlorian waste. when yoda says, "luminous beings are we" he's describing how someone is full of glowing damaging midichlorian poop. a lightsaber draws this toxic waste out of a jedi's body like tanuki foot pads, stores it, and focuses it as a weapon. midichlorian poop behaves EXACTLY like a light saber. Problem solved. It's how it works.

    btw: do you feel tired? do you not have as much energy as you want? As someone with innate jedi abilities, you really need to take special care of yourself. You are probably full of toxic midichlorian waste. I suggest buying my magnetic rare earth bracelets. may the force be with you.

  13. Re:The first problem in making a Lightsabre by MozeeToby · · Score: 2

    Has a lightsaber ever been totally destroyed on screen? I remember at least one being cut in half or disabled and even that would be terrifying if the power source were anti-matter. Remember, any containment failure will result in all that energy, enough to melt through a meter thick blast door in Ep 1 without concern, being released instantly.

  14. fencing by snookerhog · · Score: 3, Interesting

    I once had a discussion about light sabers with a Olympic fencing gold medalist. His job was sword fighting and his main gripe with light sabers (which was not addressed in this article) was that since the blade is made of light, it has no weight and thus the speed of your strikes is not limited by the blade in any way, only by how fast you can manipulate the handle. In his opinion (and mine) this would make saber duels quite short indeed.

    1. Re:fencing by nedlohs · · Score: 3, Interesting

      Yes, except that said duels are between people who can see the damn future. So yes you can slide them in half with a flick of the wrist, but they knew that flick was coming 5 minutes ago.

  15. Re:Noise by bughunter · · Score: 2

    Anything with a big 'ol vibrating transformer in it will make a similar noise.

    No. Those make the wokk wokk wokk sound when they transform from a 14-inch phallus that goes bzzzzzzzzrrrrrrzzzzzrrrrrrrrrrzzz into a Harley-Davidson V-Rod Muscle 1250, that goes chugchug chugchug chugchug... ROARRRRR!. My lesbian aunt keeps one in her purse.

    Oh. Sorry. I thought you said "transforming vibrator."

    My mistake.

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