The most remote world ever seen up close is a mash-up of smaller pieces.
Narrowing down the search is essential for gaining time on a high-powered telescope that could spot the hypothesized planet directly.
The dwarf planet’s ring makes astronomers question whether a long-held theory about ring and moon formation needs tweaking.
The low density of Kuiper Belt Object Arrokoth sheds light on the formation of planetesimals in the early solar system.
Researchers favor nitrogen ice as the most likely material for the mysterious interstellar object’s composition.
New observations confirm that main asteroid belt object Hygiea is round. It now fulfills all the requirements to graduate from asteroid to dwarf planet.
The New Horizons spacecraft recorded images of craters that imply an unexpected dearth of small objects in the Kuiper Belt.
Explore 10 things scientists have already learned about the most distant object visited by a spacecraft from Earth.
The flyby of Ultima Thule on New Year’s Day will give us our first glimpse of a mysterious Kuiper Belt object.