I’ve by no means been a Star Wars fan. I’ve seen solely one of many motion pictures, The Phantom Menace, and I used to be eight years outdated on the time. And but even I, as a baby, owned and performed with a type of little lightsaber toys, as have hundreds of thousands of youngsters earlier than and after me (to not point out the hundreds of thousands of youngsters yet-unborn, who won’t be spared induction into the Disney Industrial Complicated). And naturally what each youngster thinks as she or he swings that lighted plastic rod round is: I want this fucking factor was actual! Little question Disney would rake in much more cash if it bought precise lightsabers, however, ignoring the influence this might 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 plenty of laser and plasma scientists to seek out out.
Professor Emeritus, Physics, College of South Florida
The Star Wars universe lightsaber is normally related to a laser or laser beam that is ready to burn, reduce, or injury an object/goal or enemy. Technically, since their invention in 1960, now we have had many alternative sorts of lasers, and these have discovered all kinds of makes use of, from 0.001 Watt pink 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. So far as burning or slicing, we have already got industrial lasers which might be used to weld automotive our bodies and reduce metallic plates. Nonetheless, the ability provides that these lasers use are normally the scale of a giant suitcase and weigh about 50 lbs (not precisely conducive to saber-wielding). As well as, laser beams come in several colours or wavelengths, so this facet is already there.
The one facet of lightsabers that appears infeasible is the idea of its appearing as a strong bodily rod or saber that may “hit” or “strike” an opponent. Within the motion pictures the mechanical hitting of the dueling lightsabers is enforced by sound results—the lightsabers have a “hum,” and you’ll hear them hitting one another. However in the event you take two flashlight beams and cross one beam with the opposite beam, there isn’t any sound or power skilled by one gentle beam on the opposite. It is because photons don’t have any mass, which implies that a laser or optical beam has no mass. To get the purpose throughout: I wish to say that “You possibly can’t use a light-weight beam to hammer a nail.” So on this sense, it’s not possible that two laser beams can “hit” one another within the mechanical sense. Nonetheless, there’s a scientific exception to this: as found by latest physics Nobel Prize winner A. Ashkin, a laser beam underneath the suitable situations can be utilized as an optical lure or as an optical tweezer to lure and transfer very small objects, akin to a micro organism. Whereas one may stretch the reality and name this a Star Wars Tractor Beam, there’s a 1,000 billion billion instances 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 will not 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 ambiance, and the photo voltaic wind of plasma that causes the northern lights. However find out how to create a secure rod of plasma within the ambiance? A method 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 way has been demonstrated underneath laboratory situations utilizing a femtosecond laser, and will yield a glowing plasma saber, albeit one with a restricted lifetime. Nonetheless, a number of of the problems famous above would nonetheless restrict the usefulness of this plasma saber.
So in abstract, among the physics features of the lightsaber might be proven to be theoretically potential, however most of the sensible options are orders of magnitude away from actuality and even risk. However it will nonetheless be enjoyable to strive.
Professor, Photonics, Niagara Faculty, Canada
You’d be stunned what number of instances I’ve been requested this one.
First, let’s think about using a laser (my favourite). Think about a beam of sunshine like that from a strong laser. One of many attention-grabbing qualities about laser gentle is that it’s collimated—it travels in a straight beam that has little divergence. A daily 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’s going to preserve its “energy” to chop/destroy/and many others. for a protracted distance from the laser (be it 10 cm, 1 m, or maybe even 100 m). From that standpoint, it will be very best for our lightsaber.
Downside is, gentle doesn’t simply cease in free house. To construct a lightsaber we’d want to plot a strategy 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 may by no means discover a strategy 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.
May we use a particle apart from a photon? Say, one thing like a pion, which may journey some fastened distance after which decay (and in doing so “cease”)? Maybe, however we don’t know of any particles that might preserve lethality till some level the place they only disappear. Possibly at some point we are able to “design” such a particle, however immediately, that is strictly the stuff of science fiction. I’d add that particle accelerators are enormous beasts when it comes to kilometers in size—the laser is a greater wager for miniaturization.
Maybe the perfect method, utilizing present expertise, could be a plasma: a sizzling stream of ionized fuel molecules confined by a big magnetic area. This could require a fuel provide. The confining magnetic area is the arduous half, although—it will be enormous, and require an immense quantity of energy—so, hardly sufficiently small to slot in the palm of the hand, however at the very least “doable” in principle with present expertise.
Again to the laser, the issue is having the beam simply cease in free house. Effectively, it’s type of potential to do that proper now. Our present understanding of physics does certainly permit us to cease or “freeze” photons inside a crystal. If this may very well be utilized to the “shaft” of the lightsaber, and executed in free house versus a photonics crystal, it’d effectively be potential to create a 1 m lengthy beam of sunshine wherein radiation stays trapped inside that space (and if the ability is excessive sufficient, something touching that beam could be destroyed).
Now trapping a number of photons in a crystal inside a lab (been executed) and making a hand-held lightsaber are two various things, however at the very least the fundamental physics are, whereas “not there but,” at the very least supporting of the thought of a trapped beam of sunshine.
However that, don’t go on the lookout for it at your native gun store simply but. (I’m pondering of the Terminator scene with the plasma rifle right here).
Professor, Physics, Baylor College
A lightsaber is, in line with Wikipedia at the very least, a magnetically confined plasma. That is smart, as one factor that lightsabers are good for is slicing via numerous supplies, and we already use plasma torches to chop via dense supplies like metal. Nonetheless, the flames utilized in a plasma torch are only some inches lengthy, because the torch is ionizing fuel that flows via 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 ambiance and misplaced vitality.
So the issue is to maintain the plasma, preserve the plasma particles from colliding with the impartial air, and prolong the space over which the plasma has vitality.
One truly can confine charged particles (plasma) in a magnetic bottle, however the issue is that the “bottle” leaks at each ends, so the plasma rapidly escapes. Present state-of-the-art physics does make use of a magnetic area to restrict plasmas, particularly for the usage of fusion reactors. To get round the truth that a linear bottle leaks at each ends, the magnetic area traces are curved to create a doughnut—no ends! Nonetheless, the plasma nonetheless leaks out in several instructions, amongst different issues, and the magnetic fields wanted are fairly complicated. (For this reason we nonetheless don’t have fusion vitality, however we’re engaged on it.)
Again to the sunshine saber—the magnetic area will comprise the charged particles, however it has no impact on the impartial fuel particles within the air. Maybe 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 top. Observe that the magnetic area has no impact on impartial particles, so it may possibly’t preserve the atmospheric fuel out of the magnetic bottle.
The colour of the plasma glow is set by the atomic vitality ranges within the fuel which is ionized. Thus neon plasmas are pink 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.” That 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 distinct vitality degree for the electron transitions. A robust Jedi may use the power to vary the vitality and excite a distinct transition degree—however in an earth-like ambiance, the first fuel is nitrogen, so the glow will likely 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 ambiance by the earth’s magnetic area, and at totally different altitudes (and energies) many alternative gases are excited, producing an array of colours.
One of many vital traits of the lightsaber is that it may be deflected by one other lightsaber. On this case, the plasma must be actually dense—at the very least as dense as metal. This goes again to how effectively the magnetic bottle is designed to lure the plasma. It could not solely must lure the plasma, however acquire additional fuel from the encompassing ambiance to pay attention it right into a excessive sufficient density. (Query: does a lightsaber work in outer house?) I suppose it’s potential that there may very well be a configuration of the magnetic fields such that the magnetic fields of two totally different gentle sabers repel one another.
Do you could have a burning query for Giz Asks? E mail us at email@example.com.