Asteroids Asteroids can be as big as a grain of sand to many miles long. one of the famous asteroids is gaspra. asteroids are formed from rock and metal just like the rest of the solar system. asteroids were made from the gasses of the primordial solar nebula. the asteroid belt is three times farther away from the sun than earth. Asteroids are smaller than meteors. asteroids are shaped like spheres elongated spheres and peanut shapes. asteroids are from the asteroid belt which is in between mars and jupiter. some asteroids are given names. asteroids are gray dark red and black. the longest asteroid is 590 miles long.