Ceres Is 25% of the Asteroid Belt

Ceres is the largest object in the asteroid belt and, by NASA’s estimate, holds 25% of the belt’s total mass. With a radius of 476 kilometers (296 miles), it is about 1/13 the radius of Earth. Its own gravity pulled it into a sphere, which is why it counts as a dwarf planet.

The surface is rock and dust with large salt deposits, made of minerals such as magnesium sulfate rather than table salt. NASA says Ceres could be as much as 25% water, which would give it more water than Earth has. It orbits 2.8 times as far from the Sun as Earth does, at an average distance of 413 million kilometers (257 million miles).