柯伊伯带天体

The Kuiper Belt is a disk region past Neptune in the Solar System. Pluto's orbit is in the Kuiper Belt. Two other icy satellites lie there too, Haumea and Makemake. When the solar system formed, much of the gas, dust and rocks pulled together to form the sun and planets. The planets then swept most of the remaining debris into the sun or out of the solar system. But bodies farther out remained safe from gravitational tugs of planets like Jupiter, and so managed to stay safe as they slowly orbited the sun. The Kuiper Belt and its compatriot, the more distant and spherical Oort Cloud, contain the leftover remnants from the beginning of the solar system and can provide valuable insights into its birth.

The Kuiper Belt is like a trash can around the Solar System. Neptune's largest moon Triton is thought to have came from the Kuiper Belt. Some other moons might have originated there too.