Reminds me of https://en.wikipedia.org/wiki/Crookes_radiometer https://en.wikipedia.org/wiki/Crookes_radiometer People thought the motion was due to radiation

Reminds me of https://en.wikipedia.org/wiki/Crookes_radiometer https://en.wikipedia.org/wiki/Crookes_radiometer People thought the motion was due to radiation pressure at first but the force due to light is probably a few orders of magnitudes off. Turns out it was heat causing the motion.