Are Lightsabers Theoretically Possible?

I’ve by no means been a Star Wars fan. I’ve seen solely one of many films, The Phantom Menace, and I used to be eight years previous on the time. And but even I, as a toddler, owned and performed with a kind of little lightsaber toys, as have thousands and thousands of youngsters earlier than and after me (to not point out the thousands and thousands of youngsters yet-unborn, who won’t be spared induction into the Disney Industrial Complex). And after all what each youngster thinks as she or he swings that lighted plastic rod round is: I want this fucking factor was actual! No doubt Disney would rake in much more cash if it bought precise lightsabers, however, ignoring the affect this may need on lightsaber-related crime, the query then turns into: are precise lightsabers even potential, scientifically? For this week’s Giz Asks, we reached out to numerous laser and plasma scientists to search out out.

Professor Emeritus, Physics, University of South Florida

The Star Wars universe lightsaber is normally related to a laser or laser beam that is ready to burn, lower, or harm an object/goal or enemy. Technically, since their invention in 1960, we now have had many various sorts of lasers, and these have discovered all kinds of makes use of, from 0.001 Watt crimson lasers used to scan the UPC code at grocery checkouts, eye-safe 1 Watt IR lasers used to map buildings and roadways utilizing lidar (laser radar), to distant sensing utilizing laser probes to measure the earth’s ozone gap and CO2 ranges. As far as burning or chopping, we have already got industrial lasers which might be used to weld automobile our bodies and lower metallic plates. However, the facility provides that these lasers use are normally the dimensions of a big suitcase and weigh about 50 lbs (not precisely conducive to saber-wielding). In addition, laser beams come in numerous colours or wavelengths, so this facet is already there.

The one facet of lightsabers that appears infeasible is the idea of its performing as a strong bodily rod or saber that may “hit” or “strike” an opponent. In the films the mechanical hitting of the dueling lightsabers is enforced by sound results—the lightsabers have a “hum,” and you may hear them hitting one another. But in the event you take two flashlight beams and cross one beam with the opposite beam, there isn’t a sound or power skilled by one gentle beam on the opposite. This is as a result of photons haven’t any mass, which signifies that a laser or optical beam has no mass. To get the purpose throughout: I prefer to say that “You can’t use a light beam to hammer a nail.” So on this sense, it isn’t possible that two laser beams can “hit” one another within the mechanical sense. However, there’s a scientific exception to this: as found by current physics Nobel Prize winner A. Ashkin, a laser beam below the correct situations can be utilized as an optical lure or as an optical tweezer to lure and transfer very small objects, reminiscent of a micro organism. While one might stretch the reality and name this a Star Wars Tractor Beam, there’s a 1,000 billion billion occasions distinction between shifting a micro organism and the mass of a starship (ie. SpaceX second stage starship.)

All of that mentioned, it may be argued that the lightsaber shouldn’t be a laser beam however is as a substitute made up of a gaseous high-temperature plasma or a plasma-like tube. Plasmas are high-temperature, gaseous discharges consisting of electrons and ions at temperatures of round 5,000 to 10,000 C or larger, and are represented by the fuel discharge inside a fluorescent tube, a lightning bolt within the environment, and the photo voltaic wind of plasma that causes the northern lights. But create a secure rod of plasma within the environment? One approach is to make use of a high-power laser and focus it to a spot within the air such that you’ve Laser Induced Breakdown Spectroscopy (LIBS), which creates a plasma spot within the air, which then emits the fluorescent gentle from the plasma ball; then, by correct adjustment of laser energy and optical alignment, an elongated filament or plasma within the air might be created. Such a method has been demonstrated below laboratory situations utilizing a femtosecond laser, and will yield a glowing plasma saber, albeit one with a restricted lifetime. However, a number of of the problems famous above would nonetheless restrict the usefulness of this plasma saber.

So in abstract, a few of the physics facets of the lightsaber might be proven to be theoretically potential, however lots of the sensible options are orders of magnitude away from actuality and even risk. But it will nonetheless be enjoyable to attempt.

Professor, Photonics, Niagara College, Canada

You’d be shocked what number of occasions I’ve been requested this one.

First, let’s think about using a laser (my favourite). Consider a beam of sunshine like that from a strong laser. One of the fascinating qualities about laser gentle is that it’s collimated—it travels in a straight beam that has little divergence. An everyday flashlight, for instance, will all the time have a beam which spreads out because it travels, it doesn’t matter what you do with the optics, however the coherent beam from a laser can have surprisingly little unfold. It will keep its “power” to chop/destroy/and many others. for an extended distance from the laser (be it 10 cm, 1 m, or even perhaps 100 m). From that standpoint, it will be excellent for our lightsaber.

Problem is, gentle doesn’t simply cease in free house. To construct a lightsaber we’d want to plot a option to have these photons of radiation go about 1.5 m after which simply magically cease—and that’s effectively past our understanding of physics. I’m not saying we might by no means discover a option to do it (heck, 100 years in the past splitting of the atom appeared fairly unrealistic), however our present understanding of physics says this simply isn’t potential.

Could we use a particle apart from a photon? Say, one thing like a pion, which might journey some mounted distance after which decay (and in doing so “stop”)? Perhaps, however we don’t know of any particles that may keep lethality till some level the place they simply disappear. Maybe sooner or later we are able to “design” such a particle, however at present, that is strictly the stuff of science fiction. I would add that particle accelerators are big beasts when it comes to kilometers in size—the laser is a greater guess for miniaturization.

Perhaps one of the best method, utilizing present know-how, could be a plasma: a scorching stream of ionized fuel molecules confined by a big magnetic subject. This would require a fuel provide. The confining magnetic subject is the onerous half, although—it will be big, and require an immense quantity of energy—so, hardly sufficiently small to slot in the palm of the hand, however at the least “doable” in idea with present know-how.

Back to the laser, the issue is having the beam simply cease in free house. Well, it’s sort of potential to do that proper now. Our present understanding of physics does certainly enable us to cease or “freeze” photons inside a crystal. If this could possibly be utilized to the “shaft” of the lightsaber, and performed in free house versus a photonics crystal, it’d effectively be potential to create a 1 m lengthy beam of sunshine by which radiation stays trapped inside that space (and if the facility is excessive sufficient, something touching that beam could be destroyed).

Now trapping a couple of photons in a crystal inside a lab (been performed) and making a hand-held lightsaber are two various things, however at the least the essential physics are, whereas “not there yet,” at the least supporting of the concept of a trapped beam of sunshine.

Notwithstanding that, don’t go in search of it at your native gun store simply but. (I’m pondering of the Terminator scene with the plasma rifle right here).

Professor, Physics, Baylor University

A lightsaber is, based on Wikipedia at the least, a magnetically confined plasma. That is sensible, as one factor that lightsabers are good for is chopping by means of numerous supplies, and we already use plasma torches to chop by means of dense supplies like metal. However, the flames utilized in a plasma torch are just a few inches lengthy, because the torch is ionizing fuel that flows by means of a nozzle. A brief distance from the electrodes contained in the torch, the electrons and ions within the fuel have collided with the impartial fuel within the environment and misplaced vitality.

So the issue is to maintain the plasma, maintain the plasma particles from colliding with the impartial air, and prolong the space over which the plasma has vitality.

One really can confine charged particles (plasma) in a magnetic bottle, however the issue is that the “bottle” leaks at each ends, so the plasma shortly escapes. Current state-of-the-art physics does make use of a magnetic subject to restrict plasmas, particularly for using fusion reactors. To get round the truth that a linear bottle leaks at each ends, the magnetic subject strains are curved to create a doughnut—no ends! However, the plasma nonetheless leaks out in numerous instructions, amongst different issues, and the magnetic fields wanted are fairly complicated. (This is why we nonetheless don’t have fusion vitality, however we’re engaged on it.)

Back to the sunshine saber—the magnetic subject will comprise the charged particles, nevertheless it has no impact on the impartial fuel particles within the air. Perhaps that is what determines the size of the sunshine saber, and the plasma must be very dense in direction of the hilt and fall off in direction of the tip. Note that the magnetic subject has no impact on impartial particles, so it might’t maintain the atmospheric fuel out of the magnetic bottle.

The coloration of the plasma glow is decided by the atomic vitality ranges within the fuel which is ionized. Thus neon plasmas are crimson and argon plasmas are pinky-purple and oxygen plasmas are usually inexperienced. The Wikipedia article says that the colour of the lightsaber is managed by a “kyber crystal.” This is true for lasers, the place the colour of the laser gentle is managed by the transition ranges for electrons within the crystalline materials, however not true for a plasma. To get totally different colours, the lightsaber would want to make use of totally different working gases or excite a unique vitality stage for the electron transitions. A powerful Jedi might use the power to vary the vitality and excite a unique transition stage—however in an earth-like environment, the first fuel is nitrogen, so the glow will probably be purply-blue. That mentioned, check out the colours of the aurora (northern lights)—the photo voltaic wind plasma is directed to the earth’s environment by the earth’s magnetic subject, and at totally different altitudes (and energies) many various gases are excited, producing an array of colours.

One of the essential traits of the lightsaber is that it may be deflected by one other lightsaber. In this case, the plasma must be actually dense—at the least as dense as metal. This goes again to how effectively the magnetic bottle is designed to lure the plasma. It wouldn’t solely must lure the plasma, however gather further fuel from the encompassing environment to pay attention it right into a excessive sufficient density. (Question: does a lightsaber work in outer house?) I suppose it’s potential that there could possibly be a configuration of the magnetic fields such that the magnetic fields of two totally different gentle sabers repel one another.

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