They look like bright fireballs and are now called meteors. When a large meteor hits the Earth, it makes a deep crater and then shatters into smaller pieces. Now that the pieces have hit the Earth, they have become what are called meteorites. Near the city of Winslow, Arizona, you can visit the Barringer Crater. This huge crater was probably made by an iron meteor over 50,000 years ago.
Comets are patches of light that appear in the night sky from time to time.
They are not as common as meteors and most are too faint to be seen without a telescope. Comets are really balls of icy dirt which circle the Sun. When the comet comes nearer to the Sun, the heat melts some of the ice and a cloud is created around the nucleus , or center, of the comet. One of the main sources of comets is the Oort Cloud. The Oort Cloud may surround the entire Solar System.