Asteroid
A rocky or metal-rich object, smaller than a planet, that goes around the Sun.
An asteroid is a lump of rock, metal or both that orbits the Sun. Most are far too small to be round: many look like potatoes, peanuts or spinning tops. They range from boulders just a few metres wide to giants hundreds of kilometres across. The biggest object in the asteroid belt, Ceres, is about 940 kilometres wide and is now called a dwarf planet. More than a million asteroids have been found so far.
Asteroids are leftovers from the time when the planets were being built, about 4.6 billion years ago. That makes them like time capsules. When two asteroids crash, pieces can be knocked loose, and a few of those pieces eventually fall to Earth as meteorites. Almost every meteorite in museums came from an asteroid.
A wonderful example is the asteroid Vesta. Meteorites called howardites, eucrites and diogenites are thought to come from it, so people can hold pieces of Vesta in their hands. You cannot see most asteroids without a telescope, but through binoculars some look like faint stars that slowly change position from night to night.
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Level: Beginner Ages 7 and up