Visualization
ES2707  Observe an animation of meteor showers.

A "cloud" of dust and ice particles, most no larger than a grain of sand, trails behind the path of an orbiting comet. If Earth passes through this region, a meteor shower occurs. The small particles enter Earth's atmosphere at speeds of up to 160,000 kilometers per hour. Friction with gas molecules vaporizes the grains, producing bright meteor trails.

In a meteor shower, the meteors appear to originate from the same area of the sky, a region called the radiant. Most meteor showers are named for the location of their radiant: the radiant for the Perseids is in the constellation of Perseus.

  !   Click the image to see the animation.

Simulation of the Perseid meteor shower. The Perseids peak around August 12 each year, when Earth passes through the orbit of comet Swift-Tuttle. In the animation, time has been compressed. Typical meteor showers have maximum rates of tens of meteors per hour.