Asteroids, also described as mountains in space, consist of huge rocks a few feet in length to hundreds of miles long. Most asteroids orbit around Mars and Jupiter, which is referred to as the Asteroid Belt. Asteroids move at a very slow pace and it could take and hour to a half a day to notice any movement at all. They are visible for weeks or even months. Asteroids do not come close to the earth, but are millions of miles away. They can pass by the orbit of the moon though, and that causes a rapid movement that can be seen with the naked eye.