Nebular Hypothesis
The nebular hypothesis is a widely accepted theory that explains the formation of the solar system. According to this hypothesis, the solar system formed from a giant rotating cloud of gas and dust known as a solar nebula.

Key Points:
- Solar Nebula: The solar nebula was a massive cloud of gas and dust composed primarily of hydrogen and helium, as well as other elements.
- Gravitational Collapse: The solar nebula began to collapse under its own gravity, causing it to spin faster and flatten into a spinning disk.
- Formation of the Sun: The center of the spinning disk became denser and hotter, eventually forming the Sun.
- Formation of Planets: Within the disk, small particles collided and stuck together, forming planetesimals. These planetesimals then collided and merged to form protoplanets, which eventually became the planets of the solar system.
- Formation of Moons and Asteroids: Moons and asteroids were also formed in a similar manner through the accumulation of smaller bodies within the disk.
- Supporting Evidence: The nebular hypothesis is supported by observations of other star systems, which show disks of gas and dust around young stars that could potentially form planets.
In conclusion, the nebular hypothesis provides a comprehensive explanation for the origin of our solar system, describing how the Sun, planets, moons, and other celestial bodies formed from a spinning cloud of gas and dust.