A region in our outer solar system where many "short-period"
comets originate. The orbits of short-period comets are less than 200 years.
This region begins near Neptune’s orbit at 30 astronomical units (AU)
and extends to about 50 AU away from the Sun. An astronomical
unit is the average distance between Earth and the Sun. The Kuiper Belt may
have as many as 100 million comets.