Exploring Space . Meteorites and Life . Murchison Meteorite: Formation of the Oort Cloud

Impact Craters

Murchison Meteorite

Crumbs of Creation: Formation of the Oort Cloud

Slightly less than 4.5 billion years ago


	Artist's rendering of the Oort cloud

The Oort cloud is believed to be a potential source of meteorites that fall to Earth. During the planet formation process, smaller objects — including asteroids and comets — were drawn to the outer edges of the solar system. These became an immense cloud called the Oort cloud.

Every 225 million years, the solar system, with its sun, planets, stars and Oort cloud, circles the Milky Way galaxy. The stars don't follow the same orbit and sometimes come into close contact with the cloud, the sun or other stars. These close encounters can disturb the Oort cloud and spin comets directly into Earth's path.