Where do meteorites come from?
All meteorites come from inside our solar system. Most of them are fragments of asteroids that broke apart long ago in the asteroid belt, located between Mars and Jupiter. Such fragments orbit the Sun for some time-often millions of years-before colliding with Earth.
Meteorites can be huge: the biggest one ever found weighs around 60 tons, roughly twice as much as the Ahnighito meteorite at the center of this room. People have also found meteorites that are quite small, about the size of beach pebbles or even grains of sand.
The vast majority of meteorites are fragments of shattered asteroids. Asteroids are rocky bodies found mostly in the asteroid belt, between Mars and Jupiter. Jupiter is the largest planet in our solar system, and its gravity is very strong. Asteroids, which are much smaller than planets, are sometimes pulled out of the asteroid belt by the force of Jupiter's gravity. Many of these asteroids then travel toward the inner solar system—where they can collide with Earth.
A small number of meteorites are pieces of rock from the surfaces of other planets. These fragments were likely blasted off planets when they were hit by a large asteroid or comet. People have found meteorites that are definitely from the planet Mars, some of which are on display in this hall. Some meteorites might be from Mercury, but researchers are still investigating this claim.
The most famous moon rocks are those collected by astronauts who walked on the Moon. But small pieces of the Moon also occasionally reach Earth as meteorites. Such "lunar meteorites" are identical in composition to the astronauts' moon rocks, although they come from different locations-possibly even from the far side of the Moon, which never faces Earth.
Meteorites might also come from comets. Made of dust, rock and ices, comets are typically found in the outer reaches of our solar system, beyond the orbit of the planet Neptune. Scientists have identified several meteorites that might be fragments of the rocky cores of comets.
Keywords: Asteroids, Astrogeology, Astronomy, Astrophysics, Comets, Meteorites, Moon, Planets, Rocks