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How a real, physics-obeying lightsabre would work.


xG-9

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Ok it seems discussion of what a lightsabre blade would be became the topic in "How to hold a lightsabre" so I thought I'd make a new topic on it. Though this probably belongs in Gen Disc it leads off another topic in this forum so I thought I'd stick it here.

 

Qualification: (lol) I have studied physics at the 3rd year level at UBC. Admittedly I took "For science students not intending to major in physics" physics courses, but these are surprisingly in-depth and difficult, and certainly well, well beyond the "Only for credit for students not in the faculty of science" physics courses. (for those ummm...arts students...) So in-depth, as a matter of fact, that, as a biology student at the time, I had no idea what was going on as the math (eg fourier transforms) was being performed across blackboard after blackboard of strange looking physics.

 

Ok, on topic.

 

All this debate about the actual properties of a lightsabre (from the "How to hold" thread) ...which is pretty funny because they don't exist.

 

There's no way the blade could simply be light...two laser pointers don't clash when you cross beams, and they can't stop a blaster pistol. Whether blaster pistols are lasers is another good argument.

 

Moving on, the most feasible way I can think of constructing a lightsabre blade as seen would be to create a fairly strong EM field in the shape of the blade. It would be a cylindrical field with a semi-"hollow" interior. You could then inject a super-heated plazma or such into this field, and the field would contain the plazma in the shape of a blade. (a similar process is used in experimental fusion reactors...lol the size of the machines needed and the power required is ummm...will never fit in something the size of a maglite flashlight...) A very powerful laser at the base of the handle would then fire upwards into the plazma in the blade to keep it superheated.

 

This would allow for the clashing of blades, which would actually be from the repulsive force of the EM fields. And though I'm not sure of this, I can think of good reasons why such a blade would be capable of stopping both bullets and blaster shots. (whether blaster fire is from lasers or something else...like some sort of ion weapon) Though it is possible that the blade may be disrupted, or at least distorted by such. I won't go into this unless someone asks and I can't get a physics or engineering major to explain so I don't have to.

 

Other properties of the blade are that it would be near-weightless but would definately interact with the surrounding air quite significantly and produce a feel to the blade (and producing a lightsabre-like sound) and it could be stopped and distorted by properly polarized, very strong EM fields or magnets, but only at very close distances. (EM force, 1 of the 4 fundamental forces in the universe, decreases strength VERY quickly with distance, and is strong only at short distances)

 

The color of the blade would depend on the composition of the plazma, and can be affected by "impurities" in the plazma. (you might want to add these on purpose) The laser would have absolutely no consequence on the color, as you wouldn't be using a laser in the visible spectrum to heat the plazma anyways. The blade would definately glow like a movie lightsabre though, but from the superheated plazma, not the laser. And so perhaps the name "lightsabre" refers to the glow of the blade, not that the blade is a laser. (which is impossible)

 

Feel free to add or correct me, but ideally you should have taken at least 2nd year physics, engineering (perhaps except for civil and such) or be very well self-studied and be the next coming of Einstein or Hawking. :) I just tend to hear a lot of ridiculous arguments whenever I post something scientific...stuff that doesn't make any sense.

 

xG-9

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"(a similar process is used in experimental fusion reactors...lol the size of the machines needed and the power required is ummm...will never fit in something the size of a maglite flashlight...)"

 

And back in the 1950's people were saying that microchips were impossibilities. We're living science fiction.

Fnord.

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you get an A for effort, but surely there must be better things with which you can waste you time?

 

:p

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"I suppose outright stupidity and complete lack of taste could also be considered points of view. "

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Erm....if you're using a blade with an EM field...how would it cut stuff? Wouldn't it just repel it? Supposedly, from what is in the Star Wars Databank, and Lightsabre is a frozen blaster beam. And for a real life 'blaster' go to www.futurhorizons.com. Though all it really amounts to is an electrically charged spurt of water...on there at least. :p

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Erm....if you're using a blade with an EM field...how would it cut stuff?  Wouldn't it just repel it?  Supposedly, from what is in the Star Wars Databank, and Lightsabre is a frozen blaster beam.  And for a real life 'blaster' go to www.futurhorizons.com.  Though all it really amounts to is an electrically charged spurt of water...on there at least.  :p

 

Nah it'll cut just fine...though it's not really cutting. To be affected by the EM field an object would have to be fairly close to the blade and be either polarized or carry a reasonable net charge.

 

The actual "cutting" will go something like this... as the blade approaches, say, an arm, the superheated plazma will, to use a more forum-friendly term, vaporize, part of the arm as it slides close to it. This would be long before the plazma actually touches any flesh. After the flesh has been vaporized, the EM field would affect the constituent particles that were formerly part of the arm, since the particles will be polarized. (well most of them, at least...)

 

This isn't just my off-the-wall theory, it's stolen almost straight out of fusion reactor design, pretty cutting edge stuff. They actually use this, it's called "electromagnetic plazma confinement." The plazma they work with is at around 50 million degrees. So they needed to invent a way to store it and keep it away from...everything around it. Their solution helps out our lightsabres.

 

Of course the sabre blade wouldn't be 50 million degrees because...aside from the obvious reasons, the hotter the plazma, the stronger your EM confinement fields will have to be. I'd say about 15,000 degrees C should do it. That's the temperature you'll need to fully ionize your plazma....that's hydrogen plazma, btw. (and it MUST be fully ionized) That should be hot enough to cut what you want...it'll even cut through Titanium alloys.

 

And as for the databank, as we all know, I'm not talking about a starwars universe consistent lightsabre. I'm thinking of how one would actually be possible in the real world, by the laws of real-world physics.

 

This is all very possible, and would create a lightsabre that would have pretty much all the characteristics (more or less) of the ones seen in the movies...except for one thing...

 

I don't know if it's possible to project a strong, shaped EM field out of a handle like that...and this isn't one of those "we're using things they thought were impossible 25 years ago and was science fiction back then" things... I actually think it may be physically impossible to create an EM field like that extending out of a handle. But everything else would be "easy" after that. (except that with modern technology your lightsabre handle would be like the size of...your refridgerator...and that probably doesn't include your power source)

 

Hmmm I might send this to one of my wackier astrophysics profs back at UBC and see if he can think of a way to create such an EM field...lol

 

PS. Trivia question: using hydrogen plazma, which to me seems like the most practical choice, what color would the blade of the lightsabre be?

(dramatically, the "Imperial March" begins to play in the background...)

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Let me just interject that it is quite clear the Physics of our our universe are absolutely not the same in the Star Wars universe.

 

Hence any comparisons between them accomplish nothing.

 

I'm just thinking of how you could construct a lightsabre in OUR universe... :p

 

If nothing more than just for the mental exercise of it...and to point out that it's possible to create such a tool...or weapon...if someone figures out how to create this EM field that would be needed...hmmm...

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I've graduated in physics, so could try to enter the discussion :(

Tens of years ago russians were famous with their experimental plasma instalation called TOKAMAK. It was a torus where plasma was heated using electric discharge and stored using solenoid generated magnetic field. you may visit for a short review

 

http://library.thinkquest.org/17940/texts/....html?tqskip1=1

 

If we dream for a plasma type lightsaber, it should have some coils in order to generate the magnetic fields. A single solenoid in the hand definitely will not be enough, you will need another one at the opposite end of the beam.

 

BTW, do you have a nuclear power station in your pocket :blink:

 

Nik.

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I've graduated in physics, so could try to enter the discussion ;)

Tens of years ago russians were famous with their experimental plasma instalation called TOKAMAK. It was a torus where plasma was heated using electric discharge and stored using solenoid generated magnetic field.  you may visit for a short review

 

http://library.thinkquest.org/17940/texts/....html?tqskip1=1

 

If we dream for a plasma type lightsaber, it should have some coils in order to generate the magnetic fields. A single solenoid in the hand definitely will not be enough, you will need another one at the opposite end of the beam.

 

BTW, do you have a nuclear power station in your pocket :)

 

Nik.

 

Actually I was hoping we would put the nuclear reactor in the handle... :p lol!

 

Power would definately be a problem...I don't know how much energy we'd need...I have no idea how much power it'd take to contain the plazma...with the temp/pressure we're talking about I'm hoping that 200-500 kilowatts will do for the whole sabre? (give or take a factor of 10) But regardless that would require some sort of miniaturized nuclear reactor. (but 500 kilowatts is nothing for a nuclear reactor...so if they ever get small enough the amount of power would be easy) I don't know if there's a fission solution that would allow it to fit in the handle but it sure couldn't be a 50 million degree D-t reaction in the handle... :lol:

 

About the 2 solenoids...that's why I was saying it's probably physically impossible to do it...because we don't want a second solenoid at the far end of the blade, and so I don't think there's any way to create the field...but learning from the past I won't say "impossible" ... I'll say improbable. But that's the one big barrier to making this possible. And then add like a thousand years of technology and maybe you can have a mini nuclear reactor in the handle, and everything else we'll need to have miniaturized.

 

...the Tokamak was russian? hmmm you learn something new everyday. I pretty much just knew about the one at Princeton...I just read that they apparently managed to create 510 million degrees C there. That's crazy I never knew that...that's hot enough for tritium-tritium fusion I think!...

 

http://www.pppl.gov/about_pppl/pages/tftr.html

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Never in my life have I felt more like a child ;)

 

This is a bit too complicated for a Junior in high school...and I can't possibly offer any sort of idea or argument to the possibility of the saber's creation.......but wow, I didn't even know some of those words existed.

 

Who really knows, maybe well have "lightsabers" some time in the not-so-near feature. With the way mankind has been advancing, from a technological standpoint, a hundred...two hundred years... seems plausible...

I had thought that some of nature's journeymen had made men and not made them well, for they imitated humanity so abominably. - Book of Counted Sorrows

 

'Cause I won't know the man that kills me

and I don't know these men I kill

but we all wind up on the same side

'cause ain't none of us doin' god's will.

- Everlast

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But with a lightsaber, how would you stop the beam at a certain length? I mean there would have to be something there to stop it right?

You could focus it to a certain point sure, but wouldn't the light just carry on regardless after it met at that certain point unless there was something there to stop it?

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But with a lightsaber, how would you stop the beam at a certain length? I mean there would have to be something there to stop it right?

You could focus it to a certain point sure, but wouldn't the light just carry on regardless after it met at that certain point unless there was something there to stop it?

BTW I too have thought about this, the EM field the original poster mentioned would radiat and not have definate peramiters. Theoretically, if the power source was strign enogh the sabre source would be liek the light of a flashlight and extend foward till it hit something. I used to this that if a personswung it they coudl cut through the center earth, casue there is nothing to stop teh EM field to stop extending.

 

 

0HHH)========= < such is the star wars light sabre.

 

But a real life sabre woudl be

0HHH)================================================

 

 

getting weaker and weaker as you moved down teh blade creatign an inefective gradiant. THerefore we have thouroghly bunked your theory original poster and unless there is some way to FULLY shape the EM and defien ALL parameters both its shape and LEngth then a real life sabre could nto exist. Thank you SIrius for brigning up this valid point!

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Feel free to add or correct me, but ideally you should have taken at least 2nd year physics, engineering (perhaps except for civil and such) or be very well self-studied and be the next coming of Einstein or Hawking.  ;)  I just tend to hear a lot of ridiculous arguments whenever I post something scientific...stuff that doesn't make any sense.

 

xG-9

 

Or just actually know the Star Wars universe and the mechanics of it. First alot of people dont seem to realize that a blaster and lightsaber are actually both plasma(not plazma) weapons. Ergo the lightsaber is not actually a "light"saber. The mechanics of both weapons is actually already planned out to a point in the Star Wars Universe. I suggest you go buy a Star Wars Guide to Weapons and other part of title(the old version as in not Ep1 and 2)

 

Second both blaster and lightsaber do use Electro-Magnetic Fields. They also use gas packs and or cystrals pointing to the use of lasers. How lasers are involved is never really explained. I suppose it could be used for heating but it seems like there would be a better way to cause heat. The fact is however that blaster somehow use lasers to create a plasma beam which is then compressed and focused multiple times by EMs into a deadly beam.

 

To the man that says a lighsaber would wear out, slowly growing less powerful. You assume to easily that the EM would direct the plasma and energy in a straight line. It would be more logically to have the energy flowing in a circuit (circle) like formation, with constant replenishing of energy to the circuit from the hilt and the only loss of energy would be in forms of light and heat.

 

To the man that said, "Ergo, at light speed an object woudl have an infinite mass and infinate gravity, which woudl require infinite energy, therefore signalling the destruction of the universe, but its IMPOSSIBLE, in einsteins theory to reach light speed therefore star wars spaceships cant travel these distances."

 

First, gain some coherency.

 

Second, you barely unstand Einstein's Theory, Congrats.

 

Third, you mean the destruction of the universe like a black hole (infinite mass and gravity) causes the destruction of the universe?

 

Fourth, Einstein's theory states that objects can't ACCELERATE to Light Speed.

 

Fifth, in Star Wars ships reach light speed by going into Hyperspace, not by accelerating.

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exactly einsteins theory said that matter cant accelerate to light speed BECAUSE "light speed an object woudl have an infinite mass and infinate gravity, which woudl require infinite energy' nothign can gian infinate energy so i assumed you would realize that.

ANd btw, the question was directed towards the poster to explain lenght contraciton and time diolation to me mroe fully. For a black hoel to suck somethign in an object needs to cross the event horizon.

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Several quick things.

 

Why do people keep bringing up "star wars universe"? I'm contemplating how a real lightsabre would be possible in our universe, according to the laws of physics. While science fiction explanations are usually somewhat based on real science, ummm ... yeah ... for the purposes of builidng a real sabre your little star wars guide is a little pointless.

 

Plasma, Plazma... Sabre, Saber ... guess it depends what country you're from, doesn't it? Just so americans realize (or realise) ENGLISH is English, not "American"... and there are variations in the language in every country it's used. To assume that a word or spelling is incorrect, or doesn't exist, because it doesn't exist in the US, is a little ignorant.

 

No the blade wouldn't perpetuate indefinately, assuming there is a way to shape the EM field the way we want to. I am well aware the only way to do this in present day is to use a second solenoid, and if we were in fact to use only 2, again with modern technology, the blade would start out thin, get fat, and get thin again. I stated that this design for a sabre would depend on getting the EM field to do what we want without a solenoid at the far end of the blade, which may or may not be impossible... the word "impossible" has been used many times before for things such as...flying at the speed of sound.

 

As for special relativity, all the concepts and proofs for special relativity (as far as I can remember off the top of my head) are actually fairly simple to understand and, woohoo, don't even require the use of calculas or any other higher level math.

 

I applaud the people discussing it for thinking it through and using thought experiments, even if you reach the wrong conclusions. I don't know why they're being criticized ... I respect people that show the ability to think on their own (even if they end up wrong) much more than people that just memorize other people's work.

 

I could explain it...but it'd be hard to do here with only words and it'd take a long time...do a google search on special relativity. :) And if it really turns up nothing (I'm pretty sure you'll find like a thousand sites that explain it well) then maybe I can scan pages from my notes or one of my books... but it'd be a miracle if you could follow my notes... lol

 

PS. I will say this much because the terminology is bugging me a little.

 

From Einstein's famous equation, E=mc^2, we know that mass and energy are, in fact, the same thing. So what happens is, as you speed up, you gain inertial energy. And since energy actually has mass, as per the above equation, you're adding all this inertial energy "mass" to mass of your ship. And General Relativity tells us (this, by the way, involves some crazy crazy math) that mass (or energy, since they're both really the same thing) distorts space-time. The more mass and energy you have, the more you distort space-time. Your ship, or whatever, doesn't "have" gravity, gravity is simply the phenemenon of mass warping space-time.

 

Or that's the Relativistic way of looking at gravity, anyways... Particle physics and Quantum physics have a totally different way of looking at gravity... ways that I would like to say are BS but really, I don't know 'cuz I haven't spent more than a couple of seconds looking at that because, admittedly, I can't follow it at all...I don't understand what any of the damned equations are doing. lol

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Several quick things.

 

Why do people keep bringing up "star wars universe"?  I'm contemplating how a real lightsabre would be possible in our universe, according to the laws of physics.  While science fiction explanations are usually somewhat based on real science, ummm ... yeah ... for the purposes of builidng a real sabre your little star wars guide is a little pointless.

 

Plasma, Plazma... Sabre, Saber ... guess it depends what country you're from, doesn't it?  Just so americans realize (or realise) ENGLISH is English, not "American"... and there are variations in the language in every country it's used.  To assume that a word or spelling is incorrect, or doesn't exist, because it doesn't exist in the US, is a little ignorant.

 

Well 1) Cause Lightsabers are from the Star Wars Universe and this issue has been addressed before and 2) Cause there are more effective ways to have a high tech sword. 3) Useless Star Wars Guide? Heresy! 4) Ignorance

 

1) Yah this isn't really the forum do discuss this, and your going to constantly get reminders that lightsabers are from Star Wars when your in a Star Wars forum (not even really a Star Wars forum its a KOTOR 2 forum)

 

2) Take for instance a blade of near-molecule width held by EM fields, or even Vibro-Blades.

 

3) The whole point of that Star Wars guide was looking at Star Wars weapons from a physics and mechanical standpoint, a much more USELESS things to answer your questions with than a forum that has to do with suggestions for KOTOR 2

 

4) And arrogance.

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Actually, the poster is totally justified in trying to figure out how a lightsaber would work. For example, Lucas used the convention of Hyperspace, or extra-dimensional travel, to get around Einsteins general relativity. Lucas knew nothing could travel faster than light according to normal physics, so he tried to conceive of a plausible way aroudn that limitation, something that is already conceived of by scientists, although loosely. The point is, he made the effort to explain his universe.

 

This poster is doing the same thing in trying to explain limitations of a true "light" saber. Light can't reflect objects with mass, but an EM field could, the heat of plasma could go through metal, etc. It's also something that is already being tried in fusion reactors, it would produce that cool color, etc. As for other ways of making a high-tech sword, can YOU think of another conceivable technology that could reflect energy bolts with accuracy?

 

In fact, his explanation is so good it really should become the Star Wars EU reference standard.

 

 

You guys need to realize that if there is no plausible explanation for a device in a science fiction setting, it ceases to be sci-fi and becomes purely fantasy. If you don't need an explanation for how things work, that's perfectly fine, HOWEVER, some ppl like to think of Star Wars as adventures that might in the future some day be possible or nearly :)

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This may be a bit off the subject, but I just have to ask this, since the majority of you posters seem to have a pretty good understanding of physics and its ilk: What happens to an object (meaning, at the very broadest level of description, matter) when it goes into a blackhole? Is it atomized, obliterated, erased from existence, or is the result somewhere on the opposite side of the spectrum, like, is it made something "more" or "better" than it once was?

 

Or does nothing happen?........I'm also curious about wormholes...from a scientific perspective...preferably devoid of complex math equations.

 

On the topic, couldn't some sort of limiter be devised to control the blades size, length, etc. or maybe an artificial barrier around it, like glass, but porous...It seems impossible, and I'll admit, irrationally childish to think such a thing is probable......but stranger things have happend in the world...

I had thought that some of nature's journeymen had made men and not made them well, for they imitated humanity so abominably. - Book of Counted Sorrows

 

'Cause I won't know the man that kills me

and I don't know these men I kill

but we all wind up on the same side

'cause ain't none of us doin' god's will.

- Everlast

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