Comet

Comets, or "shooting stars" are relatively small, icy celestial bodies that revolve around the sun. In the comets approach to the sun, some of the ice in the comet turns into gas, thus creating a long luminous tail that streams behind the comet. Over the past 2,500 years, approximately 2,000 comets have been observed and recorded. Several hundred comets were not visible to the naked eye, and were discovered during the past few decades with the aid of astronomical instruments. Large comets were often viewed as astronomic phenomena until 1577 when Danish astronomer Tycho Brache proved that t…