Universe Today
Kuiper belt
The flat ring of icy bodies beyond Neptune, where Pluto lives and short-period comets come from.
Beyond Neptune, from about 30 to 50 astronomical units, lies a disc of leftovers from the formation of the solar system: Pluto, Eris, Makemake, Haumea and hundreds of thousands of smaller bodies. Unlike the Oort cloud it is flat, sharing the plane of the planets, and it is the source of short-period comets. New Horizons flew through it, past Pluto in 2015 and then past Arrokoth — a contact binary that looks exactly like two objects that drifted together gently and stuck.
Where it has come up lately
Related terms
Near-Earth object
An asteroid or comet whose orbit brings it inside 1.3 astronomical units of the Sun.
Asteroid and comet
Rock that stays rock, and ice that grows a tail when it gets warm.
Coma and tail
A comet's atmosphere, and the two separate tails the Sun pushes off it.
Oort cloud
A shell of icy bodies at the edge of the Sun's influence, inferred rather than observed.
Questions
What is Kuiper belt?
The flat ring of icy bodies beyond Neptune, where Pluto lives and short-period comets come from.
Why does it matter?
Unlike the Oort cloud it is flat, sharing the plane of the planets, and it is the source of short-period comets. New Horizons flew through it, past Pluto in 2015 and then past Arrokoth — a contact binary that looks exactly like two objects that drifted together gently and stuck.