Jim Macklin wrote:
I think a StarWars light saber might be possible with a
controlled magnetic field and plasma.

But it would not allow users to parry like in Star Wars. This is the
real problem with Star Wars technology. Light does not behave like
light. In Star Wars, you can have force fields which you can see
through but they repel visible laser light. Same problem in Star Trek.
A force field that repels a photon torpedo must, of necessity, be
opaque.

Star Wars is a lot worse, though. WW II battleship scenes and aerial
fights involving solid projectiles and explosives, but the recoil of
these never seems affect the ship using them. You can blow up a Ti
fighter heading straight at you, and the particles do no damage to your
ship despite the fact that they have the same mass and speed and are
now probably even more dangerous. Ships have artificial gravity, but
when one of them is shot down and tilts toward a planet, everyone falls
towards the nose (planetside) of the ship. What, the artificial gravity
always points toward the nearest planet rather than the floor of the
ship, or if it fails the planet's gravity can suddenly be felt on a
ship in orbit?

And where do these guys get off with the noise in space? Noisy
explosions (and you hear the noise at the moment of the explosion, too,
not delayed for a time while the sound travels to you -- even if you
are on a planet and it is a starship many miles above you that is
exploding). And noisy spaceships and engines. What ever happened to the
silence of "2001: A Space Odyssey" (no doubt the "music of the spheres"
was playing "Blue Danube" all along)?

But back to light sabers. Larry Niven in his stories posited a
"variable sword." This is actually a wire only one molecule thick (and
therefore extremely sharp) coiled in the handle of a flashlight-like
device. The wire can be extended out any length up to about four feet.
It is held straight and rigid by a force field that affects only the
wire -- the same type of force field that enables spaceships to crash
into planets without harm to the occupants (although they may be buried
beneath tons of rock). If this was a glowing force field, it would look
just like a light saber. So you could say that Lucas was just copying
something that Larry Niven had already invented.