Introduction :
Big Bang Theory is today’s dominant scientific theory about the origin of the universe. According to this theory. “Universe was created about 18 billion years ago from the random, cosmic explosion of a subatomic ball that hurled (spread) matter and energy in all direction. This newly created matter and energy coagulated into stars, galaxies, and planets including are earth”.
About 99% of the matter in the universe is Hydrogen (H) and helium (He) atoms. In our own solar system, clouds of H and He, orbiting the sun cooled and combined to form planets, their moons, and other countless smaller bodies.
Subtitle – 1 :
According to geologies, the earth was formed about 4.6 billion years ago. After its formation, the earth was thought to have been a huge barren ball of ice and rock devoid of oceans and atmosphere. However, the radioactive elements present deep within the planet earth combined under the force of gravity to heat the rock slowly into a molten mass that took several million years to cool down.
As cooling occurred, the matter of planet earth separates out into different layers. The matter with high density sinks to the innermost earth’s solid inner core. This core enveloped by a dense mixture of nickel and other heavy elements formed the liquid outer core surrounding the inner and outer core is the mantle of hot rock. On the surface is a thin, hardened crust of cool, black rock.
- Molten rock frequently erupted through this surface along with clouds of gases from the planet’s interior. The earth’s atmosphere began to form from these vapor clouds. The atmosphere was held in position due to earth’s gravity. This blanket of gases included carbon-dioxide, water vapor, nitrogen, hydrogen sulfide and methane. There was number of traces of oxygen (O2) at this stage.
Moisture in this air fell to the earth’s hot surface as rain. This then evaporated and fell again, eventually cooling the surface and led to the formation of oceans.
Subtitle : “ Life” has arisen on earth only due to presence of two requisites in sufficient amounts i.e
- Liquid water
- Carbon compounds.
Of all 9 plants, the only earth had a suitable combination of :
- Atmospheric gases composition
- Geological Activity
- Distance from sun