Our earth is a beautiful planet, mountains tree and sea are there, birds and animals living here. This a great land.

The earth was formed at the same time as the sun and the other planets in the solar system. About 4.6 billion years ago, a rotating cloud of dust and gas, called a nebula, contracted under the pull of gravity. The pressure and temperature at the center of the nebula became so great that it triggered a nuclear reaction. Some of the hydrogen in the world in the cloud fused into helium, releasing great amounts of energy. This was the birth of the sun. Farther from the centre, material surrounding the sun cooled and collided, building up into larger bodies, which eventually became the planets. The earth can be divided into three Zones according to its density, the outer crust, the mantle and the core in the centre. The layers below the atmosphere are also categorized as the lithosphere, hydrosphere and asthenosphere.

Earth is not completely round. It is flattened at the poles and bulges slightly at the equator. Over two –third of the earth is covered with water. Some amazing facts are about our earth.

a) Diameter at the poles: 12, 713 km

b) Diameter at the equator: 12, 756 km

c) Circumference (distance around the earth at the equator): 40,091 km.

d) Volume: about one thousand billion cu km.

e) Mass : 5.9 thousand billion, billion tones

f) Average density: 5.5 (water =1)

g) Surface area : 510 million sq km

h) Percentage of surface area covered by water: 71%

i) Age: 4.6 billion years

j) Age of the oldest-known rocks: 3.7 billion years

k) Distance to the average thickness of the crust : 20 km

l) Average thickness of the mantle: 2800 km

m) Average diameter of the core : 6964 km

n) Temperature at the centre : 4500dgreee cilices