Kuiper Belt
Topic: Origin and Evolution of the Earth and the Solar System · NCERT: Beyond NCERT
Meaning
The Kuiper belt is a doughnut-shaped zone of icy bodies beyond the orbit of Neptune. It lies about 30–50 AU from the Sun. One AU (astronomical unit) is the Earth–Sun distance, about 149.6 million km. The icy bodies are leftover building blocks from when the planets formed. The belt is the source of many short-period comets, which are comets that come back within a few hundred years or less.
Example
Pluto lives in the Kuiper belt. Under IAU Resolution B5 (24 August 2006), it was moved from "planet" to "dwarf planet" because it has not cleared its orbit of other objects.
Don't confuse with
- Asteroid belt: this is a zone of rocky bodies between Mars and Jupiter. The Kuiper belt is icy and lies far beyond Neptune.
- Oort cloud: this is a much more distant shell of icy bodies. It supplies long-period comets, while the Kuiper belt supplies short-period ones.