Meteoroids are pieces of natural space debris that orbit around a larger solar body, such as the sun. They measure about the size of a quarter and are much smaller than other objects that typically orbit. Meteoroids are made from a mix of rock and metals: mostly nickel and irons.
Meteoroids are usually fragments of other bodies, such as asteroids, planets and moons, that have broken away after a collision. When a meteoroid enters the atmosphere of a planet and begins to burn up, it is known as a meteor or, colloquially, as a shooting star. Since they're so small, meteors are typically completely destroyed before they reach the surface of the planet.