The earth is the only known planet having life. It is the third largest planet in the solar system. In comparison to others, our planet is the most comfortable one with abundant water, a magnetic field that protects from the heat and rays of the sun. The earth’s origin was created from the solar nebula. The big bang happened. The collapse of the gas cloud containing gases, dust and the particles condensed which formed the solar system. It continues growing a centimeter every year.
This aggregation has been building up for 100,000 years on the formation of the sun. Many terrestrial forms were created and are known as the different planets. However, one planet that grew in size was the earth. Over the 100 millions of years, the major part of loose debris as well as planetoids had been destroyed by a solar wind. Since almost 5 billions of years, the earth was formed where we reside now. Due to being in a molten state, the earth’s crust could have only lighter masses. The heavier masses dropped below due to earth’s own gravitational force and formed a central mass of earth. There was created a magnetic field. An atmosphere was formed containing helium and hydrogen. This was however, blown off by a solar wind.
Sometime later after 150 millions of years, the earth cooled to a level where there could be life evolved in it. The atmosphere contained several chemical compounds which are not present today as was then. This process also made the earth rich with CO2, Ammonia, Methane and Nitrogen. Further cooling, the earth formed clouds and there were rains. These rains made the great oceans. Land masses also known as the continents floated around for another million years. And the world came to be created.
The origin of life took place. Then seeding of the earth began due to cosmic action. Life forms came into existence and survived many atmospheric changes. Although life was just the pre-historic animals, man soon came into existence by the same cosmic action. The theory is debatable and let us not delve deeper into this. Considering the atmosphere then and now, many changes have taken place with life evolving as humans and with the distinction of man and woman concept and the children. Initially there were the dinosaurs and men and women struggling to survive. Later the these animals disappeared there is no clear cut theory as to what happened while man had advanced in science and was able to live through the difficult times.