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The Science of the Lightsaber 197

Smartcowboy writes "Chances are that you have seen a lightsaber at one time or another, whether on the evening news or down at the local cantina. Therefore you know that a lightsaber is an amazing and versatile device that is able to cut through nearly anything in a matter of milliseconds. Have you ever wondered how these remarkable weapons work? Where does the energy come from, and how are they able to contain that energy in a rod-like column of glowing power? In this article, you will have a chance to look inside a lightsaber and discover the source of its incredible characteristics." I was sure the blade was made from the focused hate and disappointment of the last three movies.


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The Science of the Lightsaber

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  • by eldavojohn ( 898314 ) * <(eldavojohn) (at) (gmail.com)> on Monday November 17, 2008 @12:08PM (#25786829) Journal
    Do we really need to do this again [slashdot.org]? I mean, seriously guys, it's not the same URL but it resolves to the same damn page. Would you like an easy +5 Insightful response? Just point out the lightsaber is casting a shadow!

    On top of that, this has been erroneously filed under "Technology." Let's just pause and let that sink in.

    Now I'll quote the article:
    • # A lightsaber is normally about 30 centimeters long, about the size of a large flashlight.
    • # At one end is the hand grip, belt ring and on/off switch (a.k.a., the Activation Matrix).
    • # At the other end there is the blade arc tip and stabilizing ring.
    • # Somewhere on the case (generally near the blade end of the lightsaber) you find one or two adjusting knobs for blade power and blade length.

    You are putting that into the technology category? Seriously? I am sorry, normally I roll with the it and just play along when this stuff is under Idle on the frontpage but this is ridiculous. I know I'm just one of many Slashdotters in bitchbitchbitch mode but the next time you come across an article like this put it in your damned April Fools folder and don't revisit it until then!

    Next week: The Science of NBC's "Heroes" ... filed under Biotech!

    • by Aeonite ( 263338 ) on Monday November 17, 2008 @12:11PM (#25786863) Homepage

      Here's a more appropriate lightsaber article to link to, which explores not the physical construction of the lightsaber, but rather it's mythical import.

      http://www.escapistmagazine.com/articles/view/issues/issue_156/5005-Lazer-Swords-and-Thundersabers [escapistmagazine.com]

      Yes, I wrote it.

      It's also not a 3-year-old article.

    • by Anonymous Coward on Monday November 17, 2008 @12:38PM (#25787241)

      Would you like an easy +5 Insightful response? Just point out the lightsaber is casting a shadow!

      (Stroking goatee ponderously)
      Hmmm, I say, the lightsaber *is* casting a shadow.

      • Re: (Score:3, Funny)

        by syousef ( 465911 )

        Hmmm, I say, the lightsaber *is* casting a shadow.

        I'm more interested in whether or not it has a reflection. Then I'll know if it's vampire technology or not. Just think the ultimate defence to a lightsaber might be wearing garlic around your neck!

        • by geobeck ( 924637 )

          Just think the ultimate defence to a lightsaber might be wearing garlic around your neck!

          Not wearing it, so much as eating it. Just chomp down a few cloves and your attacker won't be able to get close enough to use his lightsaber, and you just fry him with your blaster when the aroma makes him lose his concentration.

          The bonus is, it works whether or not the "vampire technology" hypothesis is correct.

    • And here is an EXTREMELY exhaustive discussion on the physics of lightsabers, in a fun sort of way.

      http://forums.fark.com/cgi/fark/comments.pl?IDLink=1406308 [fark.com]

      "Can a lightsaber cut through adamantium?"
    • Re: (Score:3, Funny)

      by Lumpy ( 12016 )

      "I know I'm just one of many Slashdotters in bitchbitchbitch mode"

      go under user options and select a different mode from the drop down. be sure to click apply and then save.

    • Penny-arcade [penny-arcade.com] has an interesting insight to your post. :P
    • True.. true...

      But many times, life imitates art. Automatic doors, wrist communicators, virtual interfaces (which includes touchscreen devices that change on context rather than warping the task to fit the existing interface), moving walkways, holograms, etc., all were once just fantasy.

      Though I agree that it's the wrong category, there should at least be a "science fiction" section where this can go... (and I think there is one).

    • I'm dismayed that they totally overlooked deeper discussions about what a lightsaber can and can't cut. Luckily Yahoo Answers is on the case [yahoo.com]
    • by Moraelin ( 679338 ) on Monday November 17, 2008 @02:54PM (#25789511) Journal

      Actually, I don't know if you realize it, but super-heated plasma is actually opaque to light.

      The photons emited in the nuclear fusion in the sun's centre, are absorbed and re-emitted and take millions of years to reach the surface. The sun is actually very close to a black body, except, of course, it radiates so much energy of its own that you can't shine a beam at it and notice that it's actually absorbed.

      A nuclear bomb's fireball, for the first couple of moments is actually opaque too, which actually helps with converting more of that energy into temperature of the fireball, thus into more rapid expansion of that air, and thus into a bigger shockwave. That's how about 50% of the energy goes into the shockwave. If it weren't for that, i.e., if that super-heated air actually let radiation pass right through, the bomb would just scorch the ground and fry anyone close enough and standing in the open, but wouldn't cause the kind of shockwave that levels concrete buildings.

      So could a lightsaber cast a shadow? Well, in much as the same way as a fluorescent tube can cast one. If it's in the way of a beam of light that's brighter than the sword's own shine, it would most definitely cast a shadow. (But, ok, in some poorly lit rooms like in the movies that doesn't seem to be nearly the case.)

      Now that road is another minefield for other reasons, so I'm not going to claim that lightsabers are "realistic" or "possible." But just saying that technically, yes, a blade of super-heated plasma could technically be opaque.

    • Would you like an easy +5 Insightful response? Just point out the lightsaber is casting a shadow!

      Even a lit light bulb casts a shadow. This is because it still interferes the passage of light through it from another light source. Even if you can't see the shadow, it is still there.

  • by mdm-adph ( 1030332 ) on Monday November 17, 2008 @12:12PM (#25786893)

    ...I don't know why everyone wonders how a fictional lightsaber could work.

    "How does it contain the plasma in a rod? Why doesn't it just go everywhere?"

    From what I remember of the movies, I don't remember there being any mention of there not being some kind of mechanical core to a lightsaber -- almost like a control rod that extended at the same time that the rod of light did. You'd never know from watching it.

    For all we know, even as works of fiction, they could just be normal swords that glow.

    • Re: (Score:3, Funny)

      almost like a control rod that extended at the same time that the rod of light did

      If you watch Episode 4, right after Vader kills Obi Wan, he's holding a silver-colored stick. So, perhaps this mechanical core doesn't retract at the same time?

      • by Bob-taro ( 996889 ) on Monday November 17, 2008 @01:05PM (#25787663)

        If you watch Episode 4, right after Vader kills Obi Wan, he's holding a silver-colored stick. So, perhaps this mechanical core doesn't retract at the same time?

        Good eye. Once the Jedi were defeated, the few survivors had to make their lightsabers from spare parts. I think Obi Wan used one of those powered telescoping radio antennas from an old land speeder.

    • Re: (Score:3, Interesting)

      by AdamThor ( 995520 )

      ...I don't know why everyone wonders how a fictional lightsaber could work.

      Neither do I. Lasers? Plasma? Mechanical core? Containment? Lenses and gyrsoscopes?

      THERE WAS NONE OF THAT. There was a guy and his typewriter and a bunch of words that, while compelling, were not true. There is no technology of the lightsaber. There is no "how it works". It doesn't work. It doesn't exist. The same is true of teleporters, holodecks, warp speed, etc.

      If someone wants to have some fun writing or reading this k

      • by geobeck ( 924637 )

        +1, and why is it you never seem to have mod points when you need them?

        On the one hand, using science fantasy devices as a catalyst to ask "How might we be able to do that?" is a valuable exercise. On the other hand, asking "How did they do that?" makes you wonder about some people's grip on reality.

  • by NecroBones ( 513779 ) * on Monday November 17, 2008 @12:13PM (#25786901) Homepage

    Well, at least they didn't show any household uses for the lightsaber that I've already covered. :)

    Lightsaber Uses for the Everyday Dark Lord [youtube.com]

    • by MsGeek ( 162936 )

      I've seen my fill of too many all-too-serious sabre videos. Folks, this is how it should be done! Have some fun with it! Most impressive!

  • I think the books and video games (particularly SW Battlefront 2) made for excellent expansion of the universe... WAAAY better than the movies. Should have left the movies to VG plot lines.

    Looking for work, know someone who is? Keep on eye open on craigslist.com http://www.bigattichouse.com/oneeyeopen.html [bigattichouse.com]
  • I recalled seeing this article at least a few years back, so I clicked the "citation" button on the site to check:

    Brain, Marshall. "How Lightsabers Work." 05 May 2005. HowStuffWorks.com.


  • This is not news. (Score:2, Informative)

    Seriously, how does stuff like this get on the front page?

  • by oodaloop ( 1229816 ) on Monday November 17, 2008 @12:24PM (#25787037)
    The Jedi ones, I mean. Everyone knows the red ones run Windows.
  • by NiteShaed ( 315799 ) on Monday November 17, 2008 @12:24PM (#25787043)

    and apparently there's a lot of trick photography involved in those movies. First of all, the blade is just plastic segments, and you kind of flick it to get the blade to extend. By the way, it doesn't cut worth a damn. It seems that the "light" part of the lightsaber is just a flashlight bulb embedded in the handle and shining through the tube. Pretty disappointing really.
    Now the sound effects on the other hand are pretty damn cool. Granted, they're a little tinny compared to the movies, but I figure that's just due to the way they mixed the audio in post-prod.

    • Re: (Score:3, Funny)

      That's nothing, I have a millenium falcon in my basement, but as it turns out, the real thing is plastic and only a few feet in diameter. It also only goes about 50 mph, and that's if you throw it at 50 mph.

  • I've wondered before, what would happen if you dropped one?

    Remember the rash of pulp stories in the earlier years of tethered micro black holes that were accidentally released and orbited around the inside of a planet whilst slowly gaining mass and eating more and more.

    Would a lightsaber power itself from the mass it removes/cuts - would the "battery" die out. Unlike a micro blackhole it would not generate a gravitational field.

    Really, its a slow day at work - I cannot even believe I am thinking ab
    • In the EU the Lightsabers can be fitted with a safety cut out which turns the blade off if the saber isn't being held for a period of time (to let you do the cool throwy thing). Because they're completely individual items, made by each user, how they handle stuff like that is down to the wielder.

      • by Shakrai ( 717556 )

        Because they're completely individual items

        Don't worry -- eventually China will figure out how to stamp them out of plastic for three cents a unit ;)

      • That the parent poster probably meant "Expanded Universe" [wikipedia.org] not "European Union". [wikipedia.org]

        But I guess it is a bit too late...
        Someone already mentioned China stamping out plastic ones for 3 cents per unit.
        In order to profit from the market demand for those EU and USA made lightsabers I guess.

      • Re: (Score:3, Funny)

        by TheCarp ( 96830 ) *

        In other news, Ralph Nader has brought a suit against the Jedi Council for negligence in the design of proper safety features in such a dangerous device.

        Repeatedly he has brought to their attention several design flaws which they have consistently refused to take action on. Specifically the introduction of the timed dead man's switch to comply with EU regulations was done hastily and without forethought and has created a false sense of safety and resulted in more accidents with people who felt it was now sa

    • There appears to be a conspiracy to cover up the answer: http://www.rateitall.com/i-976337-lightsaber-drop.aspx [rateitall.com]
    • by HTH NE1 ( 675604 )

      Remember the rash of pulp stories in the earlier years of tethered micro black holes that were accidentally released and orbited around the inside of a planet whilst slowly gaining mass and eating more and more.

      I liked both Thrice Upon a Time and Artifact. Are there more?

      If you haven't seen Indy Mogul's take on lightsabers [indymogul.com], you should. I loved how they used the premise of having only one real lightsaber in existence set up the gag when two real lightsabers interact with each other.

    • Re: (Score:2, Insightful)

      by qzak ( 1115661 )
      Why would you have to drop one to have it start eating everything?

      If the thing vaporizes everything, I wonder why the AIR around it survives, and you don't end up with a constant wind inwards towards the blade.
  • Am I the only one out there that thought a lightsaber would make chopping firewood a snap?
    • You don't have to chop firewood when you have a lighsaber. You just stick that slice o' tree right into your fireplace, jam your lightsaber into the middle of it and wait for it to light on fire. Mission Accomplished.
    • you can light it at the same time!

    • Am I the only one out there that thought a lightsaber would make chopping firewood a snap?

      ... and also lighting it.

  • by ShadowRangerRIT ( 1301549 ) on Monday November 17, 2008 @12:32PM (#25787165)
    Silly posts like this seem custom made for Idle, where they can be safely ignored...
  • Light sabers are boring...

    I'd much rather have a variable sword from known space which consists of a ultra-thin wire in a stasis field:

    http://www.freewebs.com/knownspace/uv.htm/#U [freewebs.com]

    Or a flashlight laser, which can be an awesome flash light, or can be narrowed into a cutting beam:

    http://www.freewebs.com/knownspace/f.htm/#F [freewebs.com]

  • Stop buying all the graflex flashguns! there are some of us out there who still use them for their intended purpose. douchenozzles.

  • This is science? (Score:2, Insightful)

    by krakround ( 1065064 )
    A lightsabre is a magic sword. How about an article on the science of the One Ring.
    • How about an article on the science of the One Ring.

      Telepathic nanocircuitry.

      1. You can control people wearing the other rings
      2. It stimulates certain parts of the brain, thus leading to it's addictive nature.
      3. It doesn't actually turn you invisible. It just makes everyone else *think* you are invisible. :)

  • Alert me when some hacker at MIT builds one. That is all.

  • by jollyreaper ( 513215 ) on Monday November 17, 2008 @01:04PM (#25787635)

    You'd have to be a Jedi to use one of these things because any average Joe is likely to cut off his own foot. A light saber represents the awesome mutilating ability of power tools combined with a form factor that's even more prone to mischief. No weight in the blade, will cause major damage with fleeting contact. They're cool but you'll be losing fingers and limbs.

    • Sure, back in the day lightsabers were the crude tools you describe, but that was a long, LONG time ago. These days, lightsabers don't arm unless they recognize the biometric signature of the person weilding them. Additionally, the factory default setting is "practice mode," and you have to do quite a bit of hacking to actually unleash their destructive potential. (No pun intended.) In "practice mode," the saber performs nearly instantaneous mass spectrometry on anything it comes in contact with, and re

    • ...than you give him credit for.

      We're able to give fairly unexceptional 16 year olds sticks which weigh about 12 ounces, fit in the palm of your hand, have exactly one button on them, and have the rule "anything extending in a ray from this hole to the horizon when the button is depressed dies". The overwhelming majority of them understand the safety precautions -- there are only four.

      1) Never point the stick at anything you do not intend to kill
      2) The stick has two states. In one, the ray coming out wh

  • by joss ( 1346 )

    They are of course perfect for making toast, slice and cook together. Steaks are doable but they turn out a bit rare.

  • by CharlieG ( 34950 ) on Monday November 17, 2008 @01:13PM (#25787785) Homepage

    All the articles about the "tech" of Star Wars, Star Trek, etc (up to an including the old Star Trek 'Engineering Manual' are nothing but mental masturbation for geeks. They are great when your in your teens, but...

    Just enjoy the show/movie

  • If you want to read news for needs, stuff that matters.

    Then try. Crowdnews [crowdnews.eu].

  • > A lightsaber is a unique device, created by hand -- the controls will be slightly different on each individual lightsaber that you buy.

    Buy? I was under the impression that each Jedi fashioned his own.

    Geek mode off...

    That said, I don't think the article works even as a parody.

    • ... often in circumstances where some "bad guys" get to pick over the remains. And there were quite a few Jedi in the past.

      It's well established in the StarWars universe that there is a big-time market in surplus/junk tech - especially items that were stolen or otherwise have chancy ownership history.

      So it seems reasonable that, along with other material picked off the losers on battlefields that isn't regulation for the winners, there would be quite a number of them for sale on various "military surplus"

  • "Therefore you know that a lightsaber is an amazing prop and optical effect that is able to cut through diddley squat in a matter of milliseconds."

    There... broke that for you! :)

  • From TFA: "A lightsaber is like a sword on steroids".

    OMG! Will people please stop using 'on steroids' this way?! I recently found that references to actual steroid use are becoming tertiary results when Googleing the term (among other things).
  • Coming up next on slashdot technology, "The Physics of Santa Claus".

  • I prefer the possibility sword from China Miéville's The Scar [amazon.com]. Imagine the Heart of Gold powering a sword so that every swing you make projects all the other swings you could have made. The more likely the swing, the more damaging the cut. The book is worth a read just for that IMO.
  • Have you ever wondered how these remarkable weapons work?

    Being somewhat connected to reality, I'd have to say no.

  • When I read the subject, I thought we'd at least get an intelligent discussion on how a Lightsaber could actually work...not this old crap with the guy lighting a cigarette again.

    I at least see the lightsaber as a variation of the Variable Sword [oinc.net] from Larry Niven's Known Space universe, where the stasis field actually emits photons of a certain frequency, causing the colored light effect.

  • Here's how it really works. . .

    You take a wooden stick, right? Or a piece of bamboo, I suppose will do. All things resonate with the force, right? Obi Wan said so. So in mundane terms, the stick has an auric signature. 'Kay. Now you record that living energetic signature into the crystal. --And yeah, sure they can do that. Everybody knows that crystals have woo-woo power.

    So now you have the auric Force signature of a wooden stick recorded in the crystal. Then through the wonders of Space Technology

  • I never understood why they were the chosen weapon of the Jedi. You can have your lightsaber. Just give me a H&K MP5. I'll collect your lightsaber from your bullet-riddled corpse.
    • I'd assumed, from the movies, that there had to be an advantage. And that the advantage was it would cut through stuff that was proof against most other weapons.

      Sample: The elephant-inspired, heavily-armored, large Imperial Walkers that were bouncing shots from ground-based heavy artillery. One fast swipe through the belly from a lightsaber and one of 'em comes apart in spectacular fashion.

  • focused hate? (Score:3, Insightful)

    by catdevnull ( 531283 ) on Monday November 17, 2008 @06:09PM (#25792923)

    Ha! Focused hate. +2 funny.

    The real source of power is the same source of power worshipped by George Lucas. The one that sucked away his soul and creativity over the last 30 years. I think they call it "ego."

Thus spake the master programmer: "When a program is being tested, it is too late to make design changes." -- Geoffrey James, "The Tao of Programming"