Most of us have grown up with the legendary sci-fi fairy tale called Star Wars. One of the most fascinating imaginary gadgets that appear in the franchise is the so called lightsaber.
As we know from the movie itself, the lightsaber is the single weapon of a Force wielder, either Jedi or Sith. It is described by Obi Wan Kenobi as “an elegant weapon, from a more civilized age”. There is an army of Star Wars fans who would give anything to be in possession of a real lightsaber. But is it possible that a lightsaber ever exists, and if it did exist, what would the consequences be?
Now let’s start with what we know about the lightsaber. It looks like a sword but instead of a sharp metal blade, it has a glowing energy blade that is able to cut with ease through almost anything. There are only few things of which we know that the lightsaber cannot cut through: the blade of another lightsaber, and an energy field similar to the blade itself. Let’s have a look at some fairly convincing schematics of a lightsaber:
While this scheme looks no less convincing than the lightsaber battles in Star Wars, it has little to do with reality. To put it simple, each component of the scheme is actually made up.
There has been a long discussion among fans about what the blade of a lightsaber is made of. The lightsaber is often incorrectly referred to as a “laser sword” by people that do not understand physics well. Once we get familiar with the properties of lasers, it is pretty much apparent that the blade of the lightsaber cannot be made of laser. There are two main reasons for that. The first one is that laser is actually a light beam and it would be completely impossible for it to act as a barrier for another light beam. To put it simple, a blade of laser can never stop another blade of laser, no matter how powerful it is.
The second reason is that it is absolutely infeasible to produce a laser that only projects at a distance of one meter and then disappears. The only way to do that is to put a thick wall in front of it. Otherwise, a laser of that power will be projected at almost unlimited distance.
If we investigate a little bit further, it seems that plasma is a much more scientifically sound material for the projection of a lightsaber blade. In order to achieve the desired properties, the blade needs to be projected from plasma and held together by a strong magnetic field. This way, it should both be able to physically stop another plasma blade, and it can also be projected at a distance of one meter if a proper magnetic field is used. Needless to say, this way we also implicitly achieve the most important feature of the lightsaber – with a temperature of several thousand degrees Celsius, such a blade would be able to cut through almost anything.
It is clear that the energy blade of a lightsaber consumes a tremendous amount of energy, which comes from the hilt of the lightsaber. Thus the hilt has two main functions: to generate plasma and project it by means of a magnetic field, and to supply the blade with the necessary amount of energy.
Unfortunately, even if we assume that we have the technology to project the blade, the biggest challenge to modern science remains. There is no power source known to mankind that can fit into the hilt of a lightsaber and provide that big amount of energy. A power generator may not suffice for the task, not to mention any battery.
There is one more thing that needs to be considered after the power source problem is resolved. We already mentioned that the temperature of the plasma blade would be several thousand degrees Celsius, which means that the hilt must completely isolate heat, otherwise the hand of the wielder will be heavily burnt in a matter of seconds.
If a lightsaber is ever constructed for real, it will certainly constitute a powerful weapon if used wisely. It has to be pointed out, however, that in the hand of an ordinary human it will never be as deadly and powerful as in the hand of a Force wielder from the Star Wars universe. In the imaginary world where the Force exists, a skilled Jedi can not only stop but even reflect the projectile of any weapon using a lightsaber, which requires inhuman dexterity and speed. But outside the fairy tale there is no such thing as the Force, and in most cases such a weapon would be inferior to ordinary guns.