Our earth is the third planet and the fifth largest. The surface under the earth is made of rocks and not as stable as it seems. There is an inner core which is surrounded by a molten outer core. These two layers are at a very high depth separated from the earth’s crust by a thick mantle.
The earth’s outer crust is a thin shell of solid rock encasing the entire globe. It ranges from 5 to 25 miles below the surface of earth.
The upper mantle extends down to a depth of about 400 miles. The mantle is solid but malleable. The solid plates of the earth’s crust drift about its molten, semi fluid upper layers. The molten magma resulting from volcanic eruptions comes from the mantle.
The outer core, estimated to be some 1400 miles in thickness is a molten mixture of iron and nickel.
The inner core is a ball of iron and nickel some 1600 miles in diameter. Despite estimated temperatures in excess of 7200 degree F, the inner core is a solid mass because of the immense pressure exerted on it. The outer crust is just a thin shell compared to the size of the globe. It is composed of a mosaic of crystal plates. The plates are moving in relation to each other.
The inner and the outer core spin at a different rate creating the earth's magnetic field. This makes earth behave like a giant electromagnet.
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