Meteorites are called finds or falls according to how they are discovered; the most productive source today is the Antarctic ice cap. The most primitive are the carbonaceous meteorites, such as Murchison and Allende.

Streams of dust particles traveling through space together produce meteor showers, in which we see meteors diverging from a spot in the sky called the radiant of the shower. Many meteor showers recur each year and are associated with particular comets that have left dust behind as they come close to the Sun and their ices evaporate (or have broken up into smaller pieces)

meteor — a small piece of solid matter that enters Earth’s atmosphere and burns up, popularly called a shooting star because it is seen as a small flash of light. meteor shower — many meteors appearing to radiate from one point in the sky; produced when Earth passes through a cometary dust stream. meteorite — a portion of a meteor that survives passage through the atmosphere and strikes the ground. most primitive — the carbonaceous meteorites, such as Murchison and Allende.