Meteors

A meteor is the streak of light that appears in the sky when a meteoroid enters Earth’s atmosphere and vaporizes due to friction with the air. The term meteor is used specifically for the light phenomenon observed in the atmosphere; if a fragment survives passage through the atmosphere and lands on the surface, it is called a meteorite. The body in space is referred to as a meteoroid.

Meteoroids vary in size from tiny grains to objects several centimeters across, with occasional much larger bodies. As they encounter Earth, they travel at high speeds, typically from about 11 to 72 kilometers per second. The intense compression and heating cause the surrounding air to ionize, producing a bright trail that can last from a fraction of a second to several seconds. Very bright meteors, or fireballs, may produce audible sounds and sometimes break apart in the atmosphere as bolides.

Color and duration of a meteor trail depend on the meteoroid’s composition and the altitude of ablation. Common colors include blue-green from magnesium and yellow-red from sodium. Most meteors disintegrate completely before reaching the ground, but a small fraction may drop meteorites.

Meteor showers occur when Earth passes through debris left by a comet or asteroid, producing numerous meteors radiating from a common point in the sky. Showers are predictable with annual peaks and are best observed from dark, clear skies away from city lights.

Meteors are studied in planetary science and astronomy to understand the composition of the solar system and the size distribution of interplanetary dust. They also contribute to the influx of cosmic material into Earth’s upper atmosphere.