Year of the Comet
Comet C/2011 L4 (PANSTARRS)

PANSTARRS information

Comet C/2012 S1 (ISON)

ISON information

Discover the Solar System

Tour the solar system: Asteroids

These small, rocky objects are leftovers from the formation of our planetary system and have changed little since that time.
By Liz Kruesi
Ceres

Asteroids are rocky objects in our solar system, but they’re too small to be considered planets. They range in size from 30 feet across (10 meters) up to about 600 miles (970 kilometers), and most reside in the space between Mars and Jupiter, known as the main asteroid belt. Although this belt contains hundreds of thousands of these objects, its total mass is only about 4 percent that of our Moon.

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