A
meteor shower is a
celestial event in which a number of
meteors are observed to radiate, or originate, from one point in the
night sky. These meteors are caused by streams of cosmic debris called
meteoroids entering
Earth's atmosphere at extremely high speeds on parallel trajectories. Most meteors are smaller than a grain of sand, so almost all of them disintegrate and never hit the Earth's surface. Intense or unusual meteor showers are known as
meteor outbursts and
meteor storms, which may produce greater than 1,000 meteors an hour. The Meteor Data Center lists about 600 suspected meteor showers of which about 100 are well established.