As the pinnacle of sci-fi movies, Star Wars features loads of cool futuristic technology, some that could possibly be real…and others that will likely remain as part of the fantasy realm. However, the high-tech nature of these inventions has not hindered geeky fans from trying to bring such technology to life – or at least figure out the science behind it! The most coveted of all these Star Wars techno-toys is, of course, the Lightsaber.
For the benefit of those uninitiated in Star Wars (very disappointing…), a lightsaber is exactly what the name suggests; it is a light sword – a weapon used by the Jedi and the Sith with a blade made of plasma, powered by a Kyber crystal, that is emitted from a metallic hilt. Lightsabers are generally used for combat and defense by Jedi, but they can cut through anything, including blast doors! The only things that it cannot slice through are materials that conduct similar levels of energy such as an electrostaff, or another lightsaber. A skilled wielder can even deflect blaster bolts and sometimes reflect them back at their enemies. A lightsaber doesn’t just do really cool stuff, it also looks incredible! That is a description of a lightsaber that true Star Wars fans can get behind.
Now, we all know that there is no such thing as a kyber crystal… and we haven’t found any similar substance out there in the universe either. Therefore, we need to figure out other ways to make a modified lightsaber. Some scientists are sold on this idea of building a lightsaber, and there have been quite a few speculations about how it could be achieved. Don Lincoln, Senior Scientist at Fermi National Accelerator Laboratory, has analyzed and figured out some details of their possible construction. Let’s take a look at what he has proposed, and then explore some other cool stuff by MIT and Harvard scientists who are trying solidify light for the same purpose.
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Plasma Blades / Cutters
All through school, we have been told that there are three states of matter: solid, liquid and gas. However, there is also a fourth state of matter called Plasma. Plasma is created by stripping a gas’ atoms of their electrons in a process called ionization, which causes the material to glow. We encounter plasma almost every day in the form of fluorescent and neon lights, as well as fire. Plasmas can get really hot (obviously…Fire!), but since the density of gas in fluorescent lights is so low, they do not heat up so much. However, if you want to build a lightsaber that can slice through almost anything, then it’s not surprising that you would need high-density plasma that will emit great amounts of heat. Fortunately, plasma torches or plasma cutters do exist.
They don’t directly cut through the material, but plasma itself is a good conductor of electricity and can convey a large electrical charge to the target material to heat it up and melt it. Voila! You have your super sharp, slice-anything sword blade.
The thing is, generating such a large flow of electric current would be a problem for a plasma tube lightsaber. The hilt does not seem to have enough space for it. In a lightbulb, for instance, the plasma is contained in the outer glass casing. How will you encase the plasma in a tubular shape, while still keeping its target-heating (or cutting) properties intact? Dr. Lincoln seems to have an answer for that too…magnetic fields!
Impact Electric Buzz and Saber Duels
So far, we have a functioning blade (but we haven’t solved the high current problem), and we have a way to create its shape. However, that is just the melting and cutting bit. If two plasma, magnetic field-contained blades were to come in contact with each other, they would just pass through one another. So you would have a lightsaber, but you couldn’t defend yourself or have epic battles? It would be like having a fancy nightlight with no capabilities as a weapon.
Wait just a moment! All we need is to find a material that could act as a core for the plasma to surround and then we can duel. This substance needs to be capable of sustaining hot temperatures without melting. Dr. Lincoln suggests ceramic, but then how could the Lightsaber be retracted so that the hilt can be carried around without harming oneself.
That is not the only obstacle Dr Lincoln mentions. Plasma that can melt metal is obviously going to be extremely hot. Heat is irradiated in the form of infrared radiation, which will burn a sword wielder’s hands. In other words, even if we figure out how to get a portable, massively powerful electric power source and invent a material (unlikely) that can pass as a core, there will still be the issue of not being able to use it safely.
Disappointed? Are you ready to give up your Jedi dream? You may be ready, but scientists are a very perseverant species. In 2013, a cool new experiment not only gave lightsaber dreamers hope, but also furthered the science related to our understanding of light. Scientists at MIT and Harvard were able to bind two photons together and make them act like atoms in a molecule!
Photons are massless entities, so if two beams of light overlap, they do not strike against each other, but simply pass through. Despite having no mass, however, a photon does have momentum when it travels. If such a photon enters a Rubidium gas cloud, which is cooled with the help of lasers, the photon transfers some of its energy to the cold atoms in the cloud, thus slowing down its speed. This energy is passed from one atom to the next and once the photon exits this cloud, it regains the lost energy and regains speed. However, when the scientist sent more than one photon through the cloud they noticed that these particles clumped together atop one another to form a molecule.
An explanation for this is the Rydberg Blockade principle, which states that in the presence of one excited atom, a nearby atom cannot be excited to the same degree. As two photons enter the atomic cloud, the first excites an atom, but must move forward before the second can excite nearby atoms. In effect, the two photons push and pull each other through the cloud as their energy is passed from one atom to the next, thus forcing them to interact. This finding has applcations for quantum logic operations and computing.
As Yoda would’ve said…strong with our scientists the Force is, wait you must in the future for Lightsaber, young Padawan!