Meteor

Meteor, bright streak of light caused when a small solid body from outer space known as a meteoroid enters the atmosphere of Earth or another planet and is heated by friction from rapid motion through the air. The outer surface of the meteoroid melts and forms an envelope of extremely hot gas and air that radiates light. The meteoroid may burn up almost completely and fall as dust, or it may fragment or explode in midair. Remains of meteoroids that reach the surface are called meteorites. The term meteor is sometimes used for the mass of rock itself. Debris from satellites, rockets, or spacecraft can also produce a bright trail as it reenters and burns up in Earth’s atmosphere.

Brilliant meteors, known as fireballs, occur singly and generally consist of a luminous head, followed by a comet-like train of light that may persist for several minutes. Bolides are bright meteors that explode with a sound like thunder. Fainter meteors, called shooting or falling stars, usually occur singly and sporadically. Meteors are easiest to see in dark night skies but also occur during daylight. See Astronomy.

Meteor showers are swarms of hundreds of meteors that appear to emanate from a fixed point in the sky. Meteor showers are named after the constellation in which they seem to have their point of origin. Examples include the Leonids (from the constellation Leo) and Perseids (from the constellation Perseus). Some appear annually on the same days of each year and are called periodic showers; others occur infrequently at varying intervals. The periods of meteor showers generally coincide with those of certain comets (see Comet). An especially intense meteor shower is called a meteor storm, when thousands of meteors may occur per hour.