Lightsabers
Scientists can imagine creating a blaster one day. When scientists talk about lightsabers, however, they have no idea how you would create one in real life.

Photo courtesy © Lucasfilm Ltd. & TM. All Rights Reserved. All Digital work by ILM.

In the movies, the way they create lightsabers is with aluminum rods. The aluminum rods are painted a fluorescent color. There are different colors for different lightsabers - think Jedi vs Sith. The rods are then wrapped in plastic shrink-wrap. The actors swing the rods around to act out the scene. The shrink-wrap keeps bits of shrapnel from flying around during all the action. Once the scene is captured on film, an artist comes along frame-by-frame and paints a glowing colored line over the rods. The sound effect person adds in the lightsaber sound effects. And the result looks and sounds great.

The use of rods gives the lightsaber two interesting properties. First, it has solidity. Second, it has a finite length. There is no way for a laser beam, a particle beam or a column of plasma to have solidity like that, and the finite length is hard to imagine too.

Photo courtesy © Lucasfilm Ltd. & TM. All Rights Reserved. All Digital work by ILM.

There is a scene in "Phantom Menace" where a Jedi Knight plunges his lightsaber into a three-foot-thick blast door and starts cutting through it. This scene is remarkable to any scientist for at least two reasons. First, the amount of energy stored in the lightsaber's little handle is gigantic. Second, the process of melting through three feet of metal would create so much heat that it would be impossible to hold the handle, much less be anywhere near the melting door.

In other words, lightsabers as portrayed in the movie are probably impossible, and we will never see them in real life.