The Birth of the SOlar System
Nebular Theory
According to the nebular theory, the sun and the planets formed from a rotating disk of dust and gases. As the speed of the rotation increased, the center of the disk began to flatten out. Matter became more concentrated in the center where the sun eventually formed.
The Growth of the Planets
The growth of the planets began as solid bits of matter began to collide and clump together through a process known as accrection. The colliding matter formed small irregularly shaped bodies called planetesimals. As the collisions continued, they grew larger and acquired enough mass to exert a gravitational pull on surrounding objects and thereby added more mass and grew into true planets.