coreaccretion

Core accretion is a leading theory explaining the formation of planets. It proposes that planets form in a protoplanetary disk of gas and dust surrounding a young star. Initially, small dust grains collide and stick together through electrostatic forces and van der Waals forces, gradually growing into larger objects called planetesimals. These planetesimals, ranging in size from a few kilometers to hundreds of kilometers, then continue to collide and merge.

As planetesimals grow larger, their gravitational influence becomes significant. They begin to attract and accrete more material, including smaller planetesimals and dust, at an accelerated rate. This process is known as accretion. For rocky planets like those in our inner solar system, this accretion continues until the body becomes massive enough to be considered a protoplanet.

For gas giants like Jupiter and Saturn, the core accretion model suggests that a substantial rocky or icy core must first form. Once this core reaches a critical mass, its strong gravitational pull allows it to rapidly accrete large amounts of hydrogen and helium gas from the surrounding protoplanetary disk. The timing and composition of the protoplanetary disk play crucial roles in determining the final size and type of planet that forms. This theory is widely accepted but still subject to ongoing research and refinement.