A disk-shaped distribution of small icy bodies, extending hundreds of astronomical units beyond Neptune, believed to be the source of the short-period comets seen in the inner solar system.
A region in our outer solar system where many short-period comets (possessing orbits of less than 200 years) originate. This region begins beyond Neptune's orbit and encompasses an estimated distance of between 30 and 100 astronomical units. There may be as many as 100 million Kuiper belt comets.
a disk-shaped region of many small icy bodies extending from just beyond Neptune's orbit to about three times further out from the Sun. It's estimated to contain more than 35,000 objects greater than 60 miles in diameter (several hundred times the number of similar-sized objects in the asteroid belt), and as many as 100 million comets 12 or so miles across. Pluto is thought to be a Kuiper belt object and not a true planet because of its small size and the extreme inclination and ellipticity of its orbit.