Life of the comet
Coma and nucleus
Structure and composition of the nucleus
The comet's tail
Tails and plasma
The Kuiper Belt and the Oort Cloud
The Kuiper Belt is a belt of objects starting just beyond the orbit of Neptune (with some objects' orbits overlapping that of Neptune). In addition to being the home of some dwarf planets and many smaller objects, it is the source of the short-period comets. The Oort Cloud is a group of objects located much farther from the Sun than the Kuiper Belt; it is the source of the long-period comets.