Asteroid

An asteroid is a small object in the Solar System that travels around the Sun. It is like a planet, but smaller. The name "asteroid" means "like a star" in the ancient Greek language. Asteroids may look like small stars in the sky, but they really do move around the Sun, while stars only seem to move because the Earth spins. Like planets, asteroids do not make their own light. Because of this, some people think "asteroids" is not a good name, and think that the name "planetoid" ("like a planet") would be a better name.

Most asteroids are made of rock, but some are made of ice or metal. Most asteroids in our Solar System are in the asteroid belt between Mars and Jupiter.

Formation

Asteroids are the leftover rock and other material from the formation of the Solar System. These rocks were too small to make a planet, and could not collide to form one. The types of asteroids include Type M, Type S, and Type C.

Discovery

In the 1800s, Gisuppe Piazzi found the first asteroid. It was named Ceres, and is the biggest object in the asteroid belt. Other asteroids, like Juno, Pallas, and Vesta were found later. Today, astronomers know of hundreds of thousands of asteroids, which range from less than a mile to 600 miles across.