The waning of the fear of comets reveals the shift brought about by the supersession of medieval cosmology (Cosmos) by early modern astronomy. In the old world view, all unusual celestial apparitions, such as comets, meteors, and shooting stars, were regarded as atmospheric phenomena, for Aristotelian cosmology only permitted complete and perfect circular orbits for the spheres of the stars, including the sun and moon. Comets, being irregular and transient phenomena, were therefore located beneath the lunar sphere (sublunar), where Creation, corrupted by t…