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
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
! Click the image to see the animation.