Belts & Clouds

- Describe the location and nature of the Kuiper Belt and Oort Cloud and show an appreciation of their associations with comets
- Describe some of the evidence for the existence of the Oort Cloud

The Kuiper Belt is a region of the Solar System outside the orbit of Neptune. It is thought to extend several times the orbit of Pluto, possibly between 100 to 1000 AU.

The region was first suggested by Gerard Kuiper as a region where large bodies such as Pluto reside as well as short period comets that orbit the Sun over hundreds of years.

The Oort Cloud was suggested as a source of long period comets by Jan Oort. It was thought that comets orbiting the Sun since the creation of the Solar System (over 4,500 million years ago) would have exhausted their supply of ices and other material.

There is no direct evidence for its existence but studies of long period orbits suggest a spherical region at between 10,000 to 20,000 AU that consists of comets that occasionally get disturbed by a passing star and consequently may send comets towards the Sun.


  • Explain the position of the Kuiper Belt and Oort Cloud
  • Explain the type of bodies thought to originate in the Kuiper Belt and Oort Cloud.