How do planets form in a solar system?

Planets form in a solar system primarily through the accumulation of gas and dust in a disc around a new star, a process known as the solar nebula theory. As a new star forms from a collapsing cloud of gas and dust, the material that does not become part of the star remains in a rotating disc around it. Over time, particles within this disc collide and stick together, gradually building up larger and larger bodies. This process can lead to the formation of planetesimals, which can further coalesce into protoplanets and eventually become full-fledged planets.

This model emphasizes the importance of the initial disc of material that surrounds a young star, which contains the building blocks for planetary formation. The gravitational attraction between particles plays a critical role, allowing them to overcome repulsive forces and aggregate into larger structures. In summary, this process highlights both the role of gravity and the initial conditions present in the protoplanetary disc for planetary formation.