Laplace’s Hypothesis, also known as the Gaseous Hypothesis, was a modified version of the Nebular Hypothesis.

1. Nebular Hypothesis:
The Nebular Hypothesis, proposed by Immanuel Kant and further developed by Pierre-Simon Laplace in the late 18th century, suggests that the Solar System was formed from a large rotating cloud of gas and dust called the solar nebula. According to this hypothesis, the solar nebula began to contract and spin due to its own gravitational pull. As it contracted, it started to flatten into a spinning disk shape with a bulge at the center.

2. Laplace’s Modification:
Laplace modified the Nebular Hypothesis by proposing what is now known as Laplace’s Hypothesis or the Gaseous Hypothesis. He suggested that the Sun and the planets were formed from a single rotating mass of gas and dust, rather than a solar nebula. According to Laplace, this original mass was a hot, gaseous disk that extended beyond the orbit of the furthest planet.

3. Formation of the Solar System:
Laplace’s Hypothesis explains the formation of the Solar System in the following steps:

a) Formation of the Sun:
The initial rotating mass of gas and dust began to contract due to gravity. As it contracted, the central region became denser and hotter, eventually forming the Sun. The contraction also caused the rotation to accelerate, leading to the formation of a spinning disk around the Sun.

b) Formation of Planets:
Within the spinning disk, particles of gas and dust started to collide and stick together, forming larger bodies called planetesimals. Through further collisions and gravitational interactions, these planetesimals grew in size to become protoplanets. Eventually, these protoplanets accreted more material and formed the planets of the Solar System.

c) Conservation of Angular Momentum:
Laplace's Hypothesis also explains the conservation of angular momentum in the formation of the Solar System. As the initial rotating mass contracted, its rotation speed increased due to the conservation of angular momentum. This increased rotation speed caused the central region to flatten into a disk shape, which is observed in the current Solar System.

4. Importance and Legacy:
Laplace's Hypothesis provided a comprehensive explanation for the formation of the Solar System and became widely accepted in the scientific community. It laid the foundation for the modern understanding of planetary formation and influenced subsequent theories in astronomy and astrophysics. Although some aspects of Laplace's Hypothesis have been refined and modified over time, it remains a significant contribution in the field of planetary science.