The Origin of the Solar System

Section: The Origin of the Solar System

1. The Solar System’s formation started approximately 4.6 billion years ago from a massive cloud of gas and dust, known as the Solar Nebula.

2. This process began with the gravitational collapse of a small part of a giant molecular cloud.

3. As it collapsed under gravity, the nebula spun and flattened into a disc, called a protoplanetary disc, with a hot, dense central core.

4. At the centre, where compression and heat were the greatest, the Sun began to form. The Sun started as a protostar, a large ball of gas and dust that becomes hot and dense enough to start nuclear fusion.

5. Around this central star, dust and gas in the protoplanetary disc began to clump together in a process called accretion. These formed the planetesimals, the building blocks of planets.

6. Over millions of years, these planetesimals collided and merged together to form the planets and moons in our solar system.

7. The inner planets, also known as terrestrial planets, are composed primarily of rocky material. These include Mercury, Venus, Earth, and Mars.

8. The outer planets, known as the gas giants, are made up mostly of gases, such as hydrogen and helium, and include Jupiter, Saturn, Uranus, and Neptune.

9. The remaining debris formed smaller objects such as asteroids, comets, and dwarf planets.

In summary, understanding the formation of the Solar System provides key insights into planetary dynamics, the life cycle of stars, and helps scientists examine the potential existence of life beyond Earth.