David Levy is an amateur astronomer. He's discovered 21 comets, both as an amateur and as part of a professional team. He recently discovered the comet that will crash into Jupiter on July 16th, and the comet is named after him. In a Smithsonian magazine article, he called this comet "the most cataclysmic event observed in our solar system since the dawn of civilization." Levy is a contributor to many astronomical magazines, and is the author of numerous books on astronomy.