Meteor Shower

A meteor shower is an event where many meteors appear in the sky over a short time. They all seem to shoot out from the same point among the stars. Meteor showers happen when Earth passes through a trail of dust and small rocks left behind by a comet or asteroid. Most meteor showers happen on the same dates every year.

A meteor is a streak of light you see when a piece of space rock burns up in Earth's atmosphere. The rocks are usually tiny, often no bigger than a grain of sand. They move incredibly fast, sometimes 160,000 miles per hour. At that speed, friction with the air heats them until they glow. People sometimes call meteors "shooting stars," but they are not stars at all.

Comets are the main source of meteor showers. A comet is a ball of ice, dust, and rock that orbits the Sun. As a comet gets close to the Sun, its ice melts and it sheds a trail of rubble behind it. That trail stays in space long after the comet is gone. Each year, Earth crosses the same trails at the same points in its orbit. That is why showers come back on a schedule.

The Perseids are one of the most famous showers. They peak every August and can produce 50 to 100 meteors per hour. The Perseids come from a comet called Swift-Tuttle, which circles the Sun once every 133 years. The Leonids arrive in November and come from Comet Tempel-Tuttle. Every 33 years or so, the Leonids produce a meteor storm with thousands of meteors per hour. The Geminids, in December, are unusual because they come from an asteroid instead of a comet. Scientists still debate why that asteroid sheds so much dust.

To watch a meteor shower, you do not need a telescope. Your eyes work better because they can see the whole sky at once. The best time is usually after midnight, when your side of Earth is facing into its path around the Sun. Dark skies help a lot, so city lights and a bright Moon can spoil the view.

Almost every meteor you see burns up high in the atmosphere and never reaches the ground. Once in a while, a bigger piece survives the fall and lands. When it lands, it becomes a meteorite. Most meteors from a shower, though, leave nothing behind except a bright streak and the memory of seeing one.