Planetsbildningen

Planetsbildningen, or planetary formation, is the process by which planets, moons, and other bodies form from the gas and dust in a protoplanetary disk surrounding a young star. This process begins with the collapse of a molecular cloud, which forms a protostar at its center. The remaining material in the cloud flattens into a disk, known as a protoplanetary disk, due to conservation of angular momentum.

Within this disk, dust particles collide and stick together, forming larger bodies called planetesimals. These planetesimals continue to grow through further collisions and accretion, eventually forming protoplanets. The largest protoplanets can gravitationally dominate their orbits, clearing out material and growing into planets.

The composition of the resulting planets depends on their distance from the star. Close to the star, temperatures are high, and only rocky and metallic materials can condense. This region is known as the terrestrial planet zone. Further out, where temperatures are lower, volatile materials like water, methane, and ammonia can also condense, leading to the formation of gas giants and ice giants.

The final stage of planetary formation involves the clearing of the protoplanetary disk, which can take millions of years. Smaller bodies like asteroids, comets, and dwarf planets may remain in the system, contributing to the diversity of objects observed in planetary systems. The study of planetsbildningen provides insights into the formation and evolution of our own solar system and the potential for life beyond Earth.