Meteoroids are particles of rock or metal in the solar system. Many scientists think that meteoroids are either bits of asteroids or comets. Meteoroids travel around the Sun in a variety of orbits.

When meteoroids reach the Earth's atmosphere, they burn up and appear as streaks of light called meteors or shooting stars. The brightest of the meteors are called fireballs. Sometimes, when meteors are burning, they are called a meteor shower.

When meteoroids hit the Earth, they are called meteorites. Meteorites vary in size.