Why do meteor showers happen?

A meteor is a space rock, called a meteoroid, that enters the Earth's atmosphere. As it rushes through the air, the air resists it and the rock becomes extremely hot. What we see as a "shooting star" is the glowing hot air around the rock as it zips across the sky. Meteoroids range in size from specks of dust to boulders, but they are almost always small enough to burn up quickly in the atmosphere.

Sometimes many meteors appear in a single night. This is a meteor shower, and it happens because of comets. As a comet travels on its lopsided path round the Sun, the Sun's heat makes it shed particles, and this debris gets spread out along the comet's path. Each year, as the Earth travels round the Sun, its orbit crosses the paths of some comets, and the Earth runs into a trail of their debris.

The meteors in a shower all seem to come from the same spot in the sky, and each shower is named after the constellation in which that spot lies. The Orionids of October, for example, seem to come from near the constellation Orion the Hunter. Other well-known showers include the Perseids in August and the Geminids in December.

How many meteors you see depends on the shower, the time of night, the state of the sky and the phase of the Moon. A full or nearly full Moon can make many meteors too hard to see.