Home › Solar System › Kuiper Belt

Fact file

Type

Belt

Distance from the Sun

6,000,000,000 km

Orbital period

249.1 years

Temperature

-230 °C on average (from -240 to -220 °C)

Interesting facts about the Kuiper Belt

• The Kuiper Belt begins beyond Neptune (30 AU) and extends to about 50 AU – a vast disc of icy bodies, about twenty times wider than the Asteroid Belt.
• This is where Pluto, Haumea and Makemake are found, along with at least 100,000 bodies more than 100 km across.
• It is thought to be the home of many short-period comets and was only confirmed in 1992, when the object 1992 QB1 was discovered.

Formation

The Kuiper Belt consists of leftovers of the icy bodies from which the outer planets formed. Far out, the material was spread too thinly to form larger planets. It is named after the astronomer Gerard Kuiper.

Composition

The bodies are too small and too cold for an atmosphere; ice only turns to gas near the Sun, forming comet tails.

Exploration

New Horizons flew past Pluto in 2015 and, in 2019, past the Kuiper Belt object Arrokoth, a snowman-like double body stuck together – the most distant object ever visited.

In comparison

The belt has only a few hundredths of Earth's mass, but stretches over an area a thousand times larger than Earth's orbit.

Test your knowledge of the Kuiper Belt

The full quiz with points and badges is in the 3D model under “Explore”.

The Kuiper Belt in the tours

• 🚀 The great journey

This site is free and has no banner ads. Here is how you can support it