No one knows just how the earth came into being. Scientists have put forward many theories about this disputed. Many scientists now believe that our Earth is about 4.6 billion years old.
The earth is a great globe of rock surrounded by an envelope of air. The earth is the only planet in the solar system with an oxygen - rich atmosphere, with both liquid water and frozen ice. About 17 percent of earth's surface is water and 21 percent is land. Water lies in basin in the rock, making oceans, seas and lakes.
Man have always been curious about the amazing planet on which he lives. Hundreds of years of hazardous endeavours by brave scientists have brought to light many startling facts about the inside and outside of the earth.