Re: Is it possible to make a radiometer chang direction and move backward?

Try to focus a beam of light onto the back (shiny) side of the blades
in a dark room. I am not sure if this would work, but it is the only
practical possibility I see.
An impractical one is to use laser cooling on the front (black) side,
but for that you have to know the composition of the gas around the
rotor and you need a laser with the correct wavelength for this gas.