What do meteorites tell us?
The most interesting aspect of a meteorite might seem to be its dramatic fall to Earth, often in a blazing fireball. But scientists spend their careers studying meteorites because they contain a record of our solar system's history going back some 4.6 billion years. By studying meteorites, we can learn details about how our solar system evolved into the Sun and planets of today—and how meteorite impacts could affect our future.
Origins of the solar system
Certain "primitive" meteorites contain the first solid material to form in our solar system. Researchers have used the age of this material—4.568 billion years—to determine the age of our solar system. Many primitive meteorites have remained essentially unchanged since they formed.
Such rocks offer a snapshot of the conditions in the early solar system. Primitive meteorites also provide clues to the proportions of the elements present in the solar system as a whole.
Meteorites from asteroids and even from other planets help scientists understand all planets in our solar system, particularly the processes taking place deep inside.
Although no one has ever been to the center of Earth, we know from meteorites that Earth has a center, or core, made of nickel and iron metal. The other planets have metal cores as well. During planetary formation, metal sinks to the center of the body, while lighter material forms a rocky crust and mantle around the outside.
Large, fast-moving asteroids or other bodies can hit Earth, the Moon or other planets with such force that they make huge craters. The Moon has millions of craters, revealing how often such bodies enter our planetary neighborhood.
The surface of Earth would also be covered with craters, but most have disappeared because of geologic changes to Earth's surface. Nevertheless, we know that Earth has occasionally been hit by large meteorites—and undoubtedly will be struck again in the future.
Keywords: Meteorites, Astrophysics, Impact, Astronomy, Planets--Origin, Solar System--Origin, Astrogeology, Asteroids, Collisions (Astrophysics)