The four stages of the solar system formation in order are:
Solar Nebula: The solar system formed from a large, rotating cloud of gas and dust called a solar nebula. As the cloud collapsed under its own gravity, it began to spin faster and flatten into a disk.
Accretion: The particles in the disk collided and stuck together, forming larger and larger clumps called planetesimals. Planetesimals grew into protoplanets and eventually into full-fledged planets.
Differentiation: As the planets grew, their interiors heated up and melted. Heavier elements sank to the center of the planets, forming cores, while lighter materials rose to the surface.
Late Heavy Bombardment: In the early solar system, there were many small bodies such as asteroids and comets that were not captured by planets. These objects bombarded the inner planets, leaving large craters and shaping the surfaces of the planets.