TV's Frink said:

I never, once, ever thought about how the lightsaber stays on.

me neither.......once I choose to accept the reality of another world or universe, or time, I also choose to accept that there will be some things about it that I dont understand and that won't be explained to me. Do I know WHY Vader's saber stays on when he throws it? No, I don't. I choose to believe he can, and it ends there.

(although perhaps there is some form of entertainment derived from trying to figure out the "why" of things in movies that we enjoy?.....not something that entertains me, but I guess it does it for some people)