The science behind the radiometer (in Mr. Willis' car) is in fact well understood, contrary to his "explanation". It does not contain a vacuum, contrary to his "explanation"; when the black sides of the vanes absorb infrared radiation from a powerful source like sunshine they heat up, warming the air which touches them and causing it to expand and push the vanes around. Body heat from the palm of a hand is not powerful enough, again contrary to his "explanation".