1.2.4 Composition of the earth
Although we cannot go to the centre of the earth, scientists believe, and have valid evidences, that the earth is composed of a core, a mantle and a crust.
- The inner core -5,150 to 6,360 km- is made from solid iron and nickel and it has a temperature of between 5,000C and 6,000C.
- The outer core -2,890 to 5,150 km- is made from liquid iron and nickel. It is responsible for the earth's magnetic field.
- The mantle -35 to 2,890 km- is made of solid rock but it flows slowly. The movements in the mantle drive the plate tectonics.
- The crust -0 to 70 km- is very thin and brittle. It is around 5 km thick under the oceans and up to 70 km under the large mountain range.