Asteroids: When planets migrate.

The article discusses research that examines the main asteroid belt, which lies between Mars and Jupiter, and shows how the migration of giant planets influenced the asteroids' orbits billions of years ago. Evidence exists to suggest that the giant planets, which consist of Jupiter, Saturn, Uranus and Neptune, have undergone migration since their formation. It is also recognized that planetesimals, which are asteroids or comets composed of rocks and ice left over from the formation of planets, can influence the migration of planets. The existence of Kirkwood gaps in asteroid orbits is discussed, and simulation models are used to evaluate asteroid populations.