Once we have the protoplanetary disk, the process of planet formation can begin. This is where the story of our familiar planets and moons truly begins.
Through a process known as accretion, small dust particles stick together over millions of years, forming larger bodies called planetesimals.
Collisions and gravitational interactions allow these planetesimals to grow into protoplanets, and eventually, into the planets we know today.
- This process also gives rise to other celestial bodies such as moons and asteroids.
- Not all material from the disk becomes part of a planet; some get scattered, and some are pushed away by solar wind once the Sun ignites nuclear fusion.
Understanding planet formation is critical as it explains features like planetary orbits, the variety of planet types, and the existence of asteroids and comets in the Solar System. This knowledge helps us comprehend how unique our Solar System is and how similar processes might occur in distant star systems.