A meteor is the streak of light you see when a small piece of space debris burns up in Earth's atmosphere. It is not the rock itself. It is the glowing trail of ionized air and vaporized material heated by friction at tens of thousands of kilometers per hour. Most meteors are caused by particles no bigger than a grain of sand, and they burn out 80 to 100 kilometers above the ground.

Bright meteors are called fireballs. If one explodes in the air, it is a bolide. If a meteor is bright enough to cast shadows, it may be called a superbolide. These events are rare but spectacular, and they are often caught on dashcams and security cameras.

Meteors arrive constantly. On any clear night, a patient observer might see a few per hour. During meteor showers, when Earth passes through the debris trail of a comet, the rate can climb to dozens or hundreds per hour. The Perseids in August and the Geminids in December are the most reliable.

The word meteor comes from the Greek meteoron, meaning thing high up. The study of meteors is called meteor astronomy, and it tells us about the composition and orbits of small bodies in the solar system.