What is the Kuiper Belt?
The Kuiper Belt is a region beyond Neptune, about 30 to 50 times Earth's distance from the Sun, containing icy bodies such as Pluto and Arrokoth.
The Kuiper Belt is a doughnut-shaped region of icy bodies lying beyond the orbit of Neptune, roughly 30 to 50 astronomical units from the Sun. It is named after the Dutch-American astronomer Gerard Kuiper, who discussed the possibility of such a region in 1951, although others also proposed similar ideas.
Discovery. The first Kuiper Belt object after Pluto, called 1992 QB1 and later named Albion, was discovered in 1992. Since then, thousands have been found.
Contents. Kuiper Belt objects are made of rock and ices, such as water, methane, ammonia and nitrogen. They include dwarf planets such as Pluto, Eris, which lies in a related scattered disc, Haumea and Makemake. Many smaller objects exist. Some have moons, and some are binaries.
Exploration. NASA's New Horizons spacecraft flew past Pluto in July 2015, revealing a geologically active world with mountains of water ice and glaciers of nitrogen. In January 2019, it flew past Arrokoth, a small, reddish two-lobed object that seems to have formed gently, preserving material from the early Solar System.
Comets. The Kuiper Belt and the scattered disc are thought to be the main source of short-period comets, such as Jupiter-family comets, which are nudged inwards by Neptune's gravity.
Meteorites? No meteorites have been confirmed as coming from the Kuiper Belt, but dust from Kuiper Belt objects and comets may reach Earth as micrometeorites.
The Kuiper Belt is a relic of the Solar System's formation, preserving clues about how the outer planets formed and moved.