Origin Of Earth
Origin of life is inseparably linked with the origin of Earth. In fact, the history of life is a chronicle of a restless Earth. The Big Bang Theory proposes that the universe had an explosive beginning. Universe originated about 15 billion years ago by a bigbang (thermonuclearexplosion) of a dense entity. About 4.5 billion years ago, our solar system was probably created when the gaseous cloud called solar nebula started to collapse under the force of Its own gravity until it became a flattened spinning disc of atoms and particles. Its central region heated up and became a star. The Sun. Atoms and the dust grains orbiting the centre of the gaseous disc then aggregated into clumps {about the size of asteroids), These clumps finally swept up all particles and grew to the Planetary size. Such as Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto. These planets and the Asteroid belt between Mars and Jupiter to the solar system originated some 4.6 billion years ago. The Earth consisted of a solid phase, the lithosphere and a gaseous envelope surrounding it, the atmosphere. The liquid phase, the hydrosphere, appeared later when the Earth cooled down to a temperature below 100′ C.
Abiogenic or Chemical origin of life:
Majority of the scientists are of the opinion that life originated from inanimate matter. Since the theory of abiogenic origin or chemical evolution of life is the only one that provides an explanation. Which can be tested. Most scientists have tentatively accepted It. Consequently, we are to limit the scope of our Inquiry to this scientific approach.