He also worked on radiation pressure from the sun and, with the assumption that the tails of comets consisted of spherical particles which reflected light well, he calculated the size of the particles in the tails.
Siya rin ay nagtrabaho sa radiation presyon mula sa Linggo, at sa palagay na ang krus ng comets consisted ng pabilog particles na reflected light ng mabuti, siya ay kinakalkula ang sukat ng particles sa krus.