If
its wikipedia article is an indication of some sort of fan consensus, that consensus is that the business end of a lightsaber is plasma, held in shape by a field of some kind, perhaps magnetic. That makes it something like a very miniaturized (by a factor of about 100,000,000)
solar coronal loop. The plasma, which is charged, follows the
flux tube, flowing out from its source – in the case of a sun, its convection zone, in the case of the lightsaber, the business end of its handle. Presumably, over thousands of Star Wars-universe years, the shape of the plasma tube was squeezed and stretched so that it no longer looked like a big, sloppy loop, but a straight blade.
Another commonplace example of a plasma tube – though not a looping one – is
lightning.
This explanation does a good job of explaining a couple of the features seen in the Star Wars movies:
- When the lightsaber is switched on (“ignited” is what most writers call it), it appears to start short, then expand to its full length, because the loop must be started short, then extended.
- When it’s switched off, the blade takes a little time to “retract” into the handle, because the loop must be smoothly shortened to avoid releasing its plasma in an inelegant, blaster-like burst.
- Though it would be damn convenient to flip a control and extend the “blade” to a few – or a few hundred – meters, this isn’t possible in the Star Wars universe, because the field emitters can’t maintain a stable plasma tube of that length
- In the real word, plasma tubes in an atmosphere – a commonplace example is lightning – ionize the air and also rarify it, producing both a crackling sound and thunderclaps. With a lighsaber’s sophisticated field shape, this “raw” sound becomes it’s “whoom” and crackle.
- Real world plasma tubes get their color from not-quite ionized gas on their fringes. To have a particular color, a lightsaber would need to spray a bit of gas of a particular composition near the blade – otherwise, it’s color would vary with the gasses in the local atmosphere, and mostly be the glaring white of lightning. A real-world example of plasma being made to have nice colors by controlling the gasses around it is a plasma globe.
- Lightsabers blades can push against one another because their plasma tube-forming fields interact, like two magnets held near one another. Why this doesn’t result in them twisting hard when in contact with one another will take greater powers of explanation than my own.
All this explaining aside, it’s important, IMHO, to remember that lightsabers were shown in the Star Wars movies not as an attempt at serious science fiction, but because they looked cool, and allowed Jedi to act more-or-less like samurai, but without old-fashion-looking swords and scabbards. Even if one could make a real device that performed exactly like the movie lightsabers, it wouldn’t necessarily be a very good weapon – to do the nifty defensive tricks like deflecting
blaster bolts, you’ve got to have superhuman Jedi speed and coordination. Unlike the blaster bolts shown in the movies, modern real world projectiles - bullets – are much too fast for a human being to see and react to, regardless of what kind of sword-like weapon one has to swat them. As
the saying goes, for real humans, it’s a very bad idea to bring a knife - or a sword, or a lightsaber - to a gunfight.
A final peeve I have with lightsabers as their shown in Star Wars, is that, for one glaring reason, they’re really crappy swords: they lack any sort of
quillions or other sort of hilt guard. If you’ve every tried fencing in anything but a very careful and friendly way with a lightsaber-sized rattan stick without any sort of guard, this lack will practically make your fingers, thumbs and wrists hurt just thinking about it. A real light saber would need some sort of guard shaped into its blade-generating field, or it would be worthless even fighting another lightsaber.
Of course, just because some fan consensus is that lightsabers involve field-contained plasma, doesn’t make this explanation any more plausible than others. I rather like the idea that they actually are some sort of
boson beam, tweaked into exotic behavior though mind-bogglingly advanced technology, even though it’s more difficult to build an explanation around this idea.
