"Katherine" wrote in message
...
Ok, here's another weird one... if light is supposed to be made up of
both
waves and particles, how much does it weigh?

E = mc^2. So a photon (light particle) has an relativistic mass equal
to its energy divided by the speed of light squared. For visible light,
a photon's energy is a few electron-volts (eV)

How much resistance do light
particles have on an airplane in flight?

It has some, yes. Physicists call it "radiation pressure" and it's
measureable in a lab. But in the air it's not much compared to the
pressure due to your average Nitrogen atom which is much more massive
(1,300,000,000 eV of energy).


Still, there has been some research into the idea of using light as means of
propulsion, either in something like solar sails or by using lasers to
bombard objects enough to cause them to move.