1. Gravity: The dust and gas particles within the nebula are constantly moving, and their mutual gravitational attraction causes them to slowly clump together.
2. Collapse: As the clumps get denser, their gravitational pull intensifies, causing them to collapse further. This collapse is fueled by the release of potential energy as particles fall closer together.
3. Heating: As the gas and dust fall inward, they collide, generating friction and heat. The core of the collapsing cloud becomes increasingly hot and dense.
4. Protostar Formation: When the core reaches a high enough temperature and pressure, it ignites nuclear fusion. This process releases enormous amounts of energy and creates a protostar, the precursor to a star.
5. Accretion Disk: The remaining gas and dust in the nebula swirls around the protostar in a disk called an accretion disk. This disk is where planets eventually form through a process called accretion, where smaller particles stick together to form larger objects.
6. Stellar Wind: As the protostar evolves into a star, it emits a powerful stellar wind that pushes away remaining gas and dust in the nebula, shaping the surrounding region.
7. Star Formation: The process of star formation can continue in the nebula, with multiple stars forming from different clumps within the cloud.
8. Planetary Systems: Within the accretion disk around the new star, planets and other objects can form through the accretion of dust and gas.
9. Dispersal: Over time, the nebula itself can be dispersed by the radiation and stellar winds from the stars that have formed within it.
In summary, within a nebula, gravity triggers the collapse of matter, leading to the formation of a protostar and accretion disk. This process ultimately results in the birth of stars and the potential formation of planetary systems.
