Cosmic Scale
Ceres
Dwarf planet · Asteroid belt
How big is Ceres?
Ceres is about 939 km across.
See Ceres in 3D, at true scale
Ceres is the largest object in the asteroid belt and the only dwarf planet inside Neptune's orbit. When it was discovered in 1801 it was called a planet; as more asteroids turned up it was reclassified, and in 2006 it was promoted to dwarf planet.
At a glance
| Diameter | 939 km |
|---|---|
| Mass | 9.38 × 10²⁰ kg |
| Diameter compared with Earth | 0.074 × Earth |
| Orbit | 4.6 years, in the asteroid belt |
| Share of the belt | About a third of its mass |
| Water | Ice and brine beneath the crust |
| Visited | Dawn, 2015–2018 |
Good to know
- The bright patches in Occator crater are salt left behind by briny water that reached the surface.
- Dawn found organic molecules, and evidence of a muddy layer of brine still present today.
- It holds more fresh water than Earth, mostly as ice.