Formation of the solar system:

This theory is based on the assvmption that the Sun and all the planets were formed from a huge rotating cloud df interstellar gas and dust. For some reasons, the cloud started contracting. The contraction was hastened by its gravitational

pull. Tlle cloud continued to contract. It also started rotating faster and became disc shaped. More and more'matter contracted towards the centre of  the disc, forming the star to be-the new Sun. The temperature of  this star rose due  to contraction until  it  started generating its own energy. Revolving around the Sun was a disc of  gas and dust from which the planets condensed. In  this revolving disc, the lighter elements were thrown towards the periphery and heavier elements concentrated  inwards. As  the Sun's energy increased, the gas shells around the inner planets were driven off  and only cores of  heavier elements in the cloud remained. The outer planets were less affected. Finally,  the bright  star's  radiation removed  the last of  the system's  free gases and a mixed array of planets remained. The smaller, solid ones were near the star and the much larger gaseous ones farther away. The Earth was the third planet.