Answer: The formation and evolution of our solar system took place over a vast period of time. It is believed that the process began about 4.6 billion years ago.
Here is a step-by-step explanation of the major events that shaped our solar system:
1. Collapse of a giant molecular cloud: A massive cloud of gas and dust in space, called a molecular cloud, began to collapse due to its own gravity.
2. Formation of a protostar: As the cloud collapsed, it formed a dense, spinning core known as a protostar. The protostar grew hotter and denser over time.
3. Formation of a spinning disk: As the protostar continued to contract, it spun faster and flattened into a disk shape due to conservation of angular momentum. This spinning disk is known as the protoplanetary disk.
4. Accretion of planetesimals: Within the protoplanetary disk, tiny particles called planetesimals began to stick together due to collisions and gravity. Over time, these planetesimals grew larger, forming protoplanets.
5. Formation of the Sun: At the center of the protoplanetary disk, the protostar reached a critical temperature and pressure, igniting nuclear fusion. This marked the birth of our Sun.
6. Formation of planets: Within the protoplanetary disk, dust and gas started to come together to form planets. This process, known as accretion, involved the gradual accumulation of more and more material.
7. Clearing of debris: As the planets formed, their gravity began to clear out the remaining gas and dust in the protoplanetary disk. This process took several million years.
8. Final stages: The planets continued to undergo processes like differentiation (separation into layers) and bombardment by comets and asteroids. These processes contributed to the final shaping of our solar system as we see it today.
So, to summarize, the formation and evolution of our solar system took around 4.6 billion years. This timeline includes the collapse of the molecular cloud, the formation of the Sun, the accretion of planets, and the clearing of debris within the protoplanetary disk.