Re: What force can make a radiometer turn backwards?

If the color of the paddles are actually opposite the visible colors for
another applied frequency then that could make it go backwards, ie although
the black paddle appears black and the white appears white, if the effective
colors were reversed for another non-visible frequency that could cause a
reverse rotation.

Alternately if there were absolutely no gas in the radiomer that actually is
the correct way for it to rotate, white receding.