pääasteroidivyöhyke

The main asteroid belt, often referred to as the pääasteroidivyöhyke in Finnish, is a toroidal-shaped region in the Solar System located roughly between the orbits of the planets Jupiter and Mars. It is populated by a large number of irregularly shaped bodies called asteroids or minor planets. The total mass of the asteroid belt is estimated to be only about 4% of the Moon's mass, with Ceres, the largest object, accounting for about a third of the total mass.

The asteroid belt is not densely packed with asteroids as often depicted in science fiction. The average distance between asteroids is vast, making collisions rare. It is thought to be composed of material that failed to coalesce into a planet during the formation of the Solar System, primarily due to the gravitational influence of Jupiter.

Asteroids within the belt vary significantly in size, from dwarf planets like Ceres to small, rocky bodies measured in meters. Their composition also varies, with inner belt asteroids tending to be rocky and metallic, while outer belt asteroids are more commonly carbonaceous. The belt is also home to some larger objects, including four dwarf planets: Ceres, Vesta, Pallas, and Hygiea. Studying the asteroid belt provides valuable insights into the early Solar System and the processes of planetary formation.