Larger meteors burn up as they enter the earth's atmosphere, creating fleeting streaks of light.
Meteor showers occur when the earth in its orbit around the Sun passes through debris left over from the disintegration of comets . Although the earth's orbit around the Sun is almost circular, most comets travel in orbits that are highly elongated ellipses. As a result, some comets have orbits that intersect or partially overlap the earth's path. The rocky debris, consisting of mostly sand-size particles , continues in an elongated orbit around the Sun close to that of its parent comet. When the earth intersects this orbit in its annual trip, it can run into this debris, which burns up on entry into the earth's atmosphere, producing a visible shower of meteors.