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.
New Horizons principal investigator tells Eos that the mission has revolutionized our understanding of small planets.
It's been 10 years since Pluto was reclassified as a dwarf planet. But no matter the label, it and its dwarf planet cousins continue to stun researchers with their complexity.
Astronomers have discovered an icy ball in the dark and frigid regions of the outer solar system, which they suspect harbors secrets to the solar system's formation and evolution.
Finding out whether just a few or many of this newfound type of rocky object roam deep space should help scientists sort among contrasting scenarios of the solar system's infancy.