Asteroids: Sizes and Shapes

Asteroids come in all different shapes and sizes. A few of the largest asteroids are nearly spherical, like the Earth. Ceres is a good example:

Asteroid Ceres


Most asteroids, however, are very irregular, like Eros (which was visited by the NEAR spacecraft in 2000):

Asteroid Eros


Ceres is also the largest asteroid, but it is still much smaller than any of the planets. The other asteroids are smaller still. This diagram shows many of the largest asteroids in comparison to each other and to Mars. The location of each asteroid indicates its place in the Main Belt and its location above or below the plane of the planet’s orbits:

Asteroid Main Belt diagram

Credit: Clark R. Chapman, “Asteroids,” in The New Solar System.

The smallest asteroids are just small rocks orbiting through space.

To find out the size and other information about any numbered asteroid, visit the Small Body Database Browser at NASA’s Jet Propulsion Laboratory (JPL) web site.

Just type in the name or number of an asteroid like 1 Ceres or 433 Eros in the box and hit “Return.” That will take you to a page with lots of information about the asteroid.