A falling star is a meteor. Meteors are streaks of light in the sky. The light is caused by a small speck of dust burning when it enters the earth's atmosphere. The dust comes from comets. These pieces of comet dust are called meteoroids.
Most meteoroids are smaller than a grain of sand.
The flash of light is called a meteor. Meteors usually last just a second or two. Sometimes, there are meteor showers. In a meteor shower, lots of shooting stars seem to fall from one area of the sky. These meteor showers happen when the Earth travels through a stream of dust following a comet.