The Earth, our unique home is just an immense ball of rock with proper mix of essential components for life at the surface, in the atmosphere, in water bodies, within and beneath the crust. It went through dramatic history of 4.5 million years with extreme environments and catastrophic transformations that eventually resulted in diverse forms of life. We now exist on its surface after a long struggle over ruins of fire, ice, violent seas, poisonous fumes and dead mass-extinctions. We are the survivals but yet for sometime, how long no one knows.
For thousands of years humans had no idea of the true age of the earth and the origin of the world. It is just in the past two hundred years scientists have explored and un-earthed its secrets through remarkable discoveries that led to tell the incredible story “How the earth was made”. It was a simple Scottish farmer “James Hutton” that triggered the generation of the enormous knowledge about the evolution of the earth. He spent years of own research with horse-expeditions around Scotland, to understand how rocks were formed from layers of sediments. Hutton finally found proves that the earth was very much older than what the Christian Church had been telling for generations. The Archbishop in the 17th century had calculated that the age of the earth was 6000 years old and indeed it was made on October the 14th on the afternoon. Hutton’s discovery was a turning point. It is now the rocks, who are the gays knowing the truth about age and evolution of the earth.
The journey of our blue-green planet began in a world full of fire and media made up of the early solar system with temperature similar to the surface of the sun. The origin of enormous heat of the earth, and the large-scale and long-time slow cooling-processes of the earth, is radioactivity. Based on heat evolved from the primordial radioactivity in the earth, uranium, thorium and potassium, Kelvin estimated that the earth would take millions of years to cool down. However, radiometric dating gives the correct age of the earth, i.e. using uranium found throughout the rocks on the earth and decaying into another element, lead. By measuring the ratio between lead and uranium trapped in rocks the view changed from millions to billions of years.
The origin of water on the earth remains to be a mystery. As the planet cools the surface of rocks burns out into carbon dioxide and together with water vapor formed thick cloudy atmosphere and toxic hostile water that remained for half billion years along yet with volcanic activity, formation of basaltic and granite rocks, ocean and continents. With radioactive dating, the scientists for the first time have tools to know the age of rocks, arrange them in systematic order and re-write the history of the evolution of the earth. With the slowly declining radioactivity and thereby removal of heat at the earth’s surface the first radical change towards a watery world took place and the formation of oceans.
Life was first appearing in the ocean and became free to move to land for 400 million years ago. For 200 million years swamps developed and later transformed to coal. Also, dead marine organisms transformed to oil and gas. These are the origin of fossil fuel, coal, oil and gas which probably required at least tens of million of years for formation and transformation. The first mass-destruction was the death of dinosaurs about 65 million years ago with appearance of mammals some 50 million years ago. Two million years ago modern humans appeared in the east coast of Africa and spread out of Africa where the ice age restricted the spread of humans further to Europe. As the last glacial retreated 10 thousand years ago, many new living conditions were further developed, e.g. with the creation of huge depressions making up many freshwater lakes and river systems in the northern hemi-sphere.