Actually, comets hit the sun all the time! Since they are mostly made of dust and ice, all that happens is the ice melts and the comet vaporizes. Take a look at these movies. The first one shows a comet flying across the face of the Sun and the second shows a comet flying through space from two points of view and disappearing behind the Sun. http://www.youtube.com/watch?v=9EDTP13Lc3w http://www.youtube.com/watch?v=DmeotJ4NxFw