What causes meteor showers?
Meteor showers happen when Earth passes through trails of dust and debris left behind by comets, or sometimes asteroids. The particles burn up in the atmosphere as streaks of light.
As a comet travels near the Sun, its ice vaporizes and releases dust and rocky particles that spread along its orbit. When Earth crosses one of these debris streams each year, many particles enter the atmosphere at high speed and burn up, creating a meteor shower. Showers happen around the same dates every year.
Because the particles travel in parallel paths, the meteors appear to come from a single point in the sky, called the radiant. Showers are named after the constellation where the radiant lies. The Perseids appear to come from Perseus, the Leonids from Leo and the Geminids from Gemini.
Best showers to watch
The Perseids, peaking around August 12 and 13, and the Geminids, peaking around December 13 and 14, are among the best, often producing 60 to 120 meteors per hour under dark skies. Occasionally, showers become meteor storms, with thousands of meteors per hour, as the Leonids did in 1833 and 1966.
Did You Know?
The Geminids are unusual because their parent body is an asteroid, 3200 Phaethon, rather than a comet.