There's a thread on another Board on LED lights. Got me to thinking about light, and propulsion.

Originally light was fire from wood, mostly. Heat supplied light. Then, refined, to kerosene. Along came incandescent lights, still heat. Fluorescent, still heat. And then LEDs. Not heat.

Propulsion is still in the chemical stages, mostly. Some experimentation with other forms, which provide weak propulsion.

I know gravity is a factor in moving mass away from mass which isn't one with light, at least at the level of normal human activity. The analogy, weak as it is, sort of provides hope there may be some feasible technology which might emerge from physics, maybe after a Theory of Everything comes along, which will allow for significant mass to escape gravity in one piece.

Arf