Earth is the fifth largest planet and the third planet from the sun. Earth is a planet about 12,756 km in diameter. It is believed to be about 4.6 billion years old. Gas and dust that were floating around the sun came together to make the earth. Heavy material became the earth’s core and the lighter material became the crust.

1. It has a fluid core mostly of Iron. It also contains oxygen, silicon, aluminium, calcium and magnesium. 86 other elements also exist on earth in natural form.
2. 70% of earth is covered with water.
3. It has a life-sustaining atmosphere i.e, about 78% nitrogen, 21% oxygen, 1% other gases like argon, helium, carbon dioxide and water vapours. Earth’s atmosphere acts as a blanket keeping the earth warm. It acts as a shield preventing the earth from the sun’s ultraviolet rays.

Earth is made up of Lithosphere (solid), Atmosphere (gases) and Hydrosphere (liquid).

• THE INNER CORE - It is the center of the earth which is about 6000 km beneath the surface of the earth. It is solid iron despite being hotter because of great pressure.
• THE OUTER CORE - It consist of molten iron, nickel and other material and is very hot.
• THE MANTLE - It lies round the outer core. It is about 900 km thick. It is made up of rocks that is so incredibly hot that ii is partly molten (liquid).
• THE CRUST - It is the outer surface of the earth. Quartz and Feldspar make up about 90% of the earth’s crust. It is the part of the earth we live on and dig into.

It has two layers

1. Continental layer - It is mostly of rocks called granite. It forms the continents like Asia, Africa, Australia etc.
2. Sub Continental layer - It is mostly of rocks called basalt. It forms the bottom of the ocean. It lies underneath the continents.

The earth crust consists of huge section of plates that are moving very slowly. The Earth’s continents and oceans rest on these plates. As the plates collide and the crust crumps up under enormous pressure , mountains are formed over millions of years.

Key Facts

• The Earth is 12,756 km in diameter at the equator.
• The diameter at the poles is 12,108 km.
• The average depth of the crust is 35 km.
• The inner core is about 2,400 km in diameter.
• Electric currents in the metallic core produces the earth’s magnetic field.