Asteroids are objects made of rock and metal that orbit the sun but are too small to be considered planets. Most asteroids revolve around the sun in an orbit between Mars and Jupiter, forming the wide band of the Asteroid Belt. Near-Earth objects are asteroids that have orbits that cross Earth's orbit. In the past, some near-Earth objects have collided with Earth, leaving huge impact craters. The study of asteroids should tell us more about how our solar system was formed.