Comets are icy bodies traveling in eleptic orbits around the Sun. They are important to scientists because the material on them has remained mostly unchanged since they were formed at the formation of the solar sytem. The most famous comet would be Halley's Comet which has an orbit of 76 years around the Sun. In 1997 Comet Hale-Bopp, another bright comet, showed itself to the world. Bright comets do not come often, but when they do they are always a treasure to see.
A comet has a few basic structures. At the head of the comet we see in the sky is a starlike core called the nucleus. The nucleus is surrounded by a cloud of dust and gas, called the coma. Trailing behind this is a long transparent tail. This part is not always clearly visible because it can be too faint to see. These are the basic components, although there is much more to these objects.