Earth – the place where human beings inhabit is 454 crore years (4.54 billion years) old. But our right understanding of the earth is very recent. Until Copernicus (1473-1543 A.D) the earth was believed to be the centre of the world. Copernicus’ book “Revolutions of the Celestial Spheres” have changed the idea of the earth and becomes the starting point of the modern astronomy. The life in earth had started some 100 crore years back. Earth is composed of many spheres. Earth is enclosed by the atmosphere and sustains the biosphere.
Earth is not static but a rotating body revolving around the Sun. It has a magnetic field and gravity. Earth’s outer crust is composed of a number of plates and is in constant movement. This creates lot of dynamism resulted in volcanic activity and earth quake. Earth’ atmosphere also is in constant movement due to the differential heating and cooling of earth and ocean. This creates another dynamism resulting in rains, cyclones, anti-cyclone, etc. Another marked movement is the ocean currents, induced due to the differential heating and cooling of water between polar and equatorial regions. All of them and many more not listed together made this most dynamic earth a wonderful planet to live!!
Planet Earth
Birth of the Solar System
How the Earth Was Made
How Was the Moon Born?
Layers of Earth
Inside Earth
What is an Eclipse?
