Text Written By: Christopher A. Davis--Owner of Alpha Centauri's Universe: The Astronomical Tour Of The Natural World

Asteroids are leftover materials from the time the solar system formed. The most popular theory is that they have not condensed into a planet like most debris in the early formation of the solar system. Asteroids only make up a very small portion of the solar system if all combined. Thus with all asteroids combined, the object's size would be roughly half the diameter of the moon.

Most asteroids are located in the asteroid belt between the orbits of Mars and Jupiter. Surprisingly, even in the asteroid belt, asteroids are far in between thus allowing spacecraft to pass through quite safely.

Meteorite have provided the most understanding of asteroids. The process of a meteorite formation is a meteroid burning up in the atmosphere as a meteor thus living any surviving materials on the surface as a meteorite.

Meteorite are a very hard find on Earth since most of them are made up of silicate (stone). The remaining few meteorite are composed of iron and nickel or a combination of three materials discussed.