The nebular hypothesis, first proposed by Immanuel Kant, suggests that the solar system formed from a large cloud of dust and gas, known as a "solar nebula." According to this hypothesis, the nebula underwent gravitational collapse, causing it to spin and flatten into a disk shape. As the materials within the nebula began to clump together due to gravitational attraction, they formed separate particles that coalesced over time to eventually form the Sun at the center and the planets in orbit around it.
In summary, the processes described by the nebular hypothesis include:
- Collapse of the nebula: A disturbance (such as a nearby supernova) triggers the collapse of the solar nebula.
- Formation of a rotating disk: As it collapses, the nebula spins faster and flattens into a disk shape.
- Coalescence of particles: Dust and gas in this disk begin to stick together through various forces, forming larger and larger bodies (planetesimals).
- Formation of the Sun and planets: The largest mass at the center forms the Sun, while other clumps develop into the planets, moons, and other solar system bodies.
Thus, the nebular hypothesis explains the origin and structure of the solar system based on the behavior of gas and dust under gravitational forces.