But some are large enough to survive and strike the ground. This surviving chunk of rock is called a meteorite . Most meteorites are of the stony type. Stony meteorites are composed of low-density materials similar to Earth's surface rocks. Irons are most commonly found because they more obviously differ from Earthly rocks.
Irons are very dense, and magnetic, and appear to have been somewhat melted by their fiery fall.
Stony-iron meteorites represent a blend between the stony and iron types At certain times during the year, the number of meteors observed increases greatly, in some cases, exceeding 60 meteors per hour. These are called meteor showers. The material that produces them appears to be debris left by comets as they pass through the solar system. The comets themselves may or may not still exist, but the material they leave behind still does, and it follows the path of the comet's orbit. Each year as the Earth crosses that comet's path, it collides with the cometary debris, and we see the meteor shower.