The Layers of the Earth

The Earth is not the same all the way through. It is made up of layers, like an onion. The thin outer layer is the crust where we live. Below the crust is the thick mantle. At the center are the outer core and inner core. Each layer is made of different materials.

The Crust and Mantle

The crust is the thin, rocky outer layer of the Earth. It is where we live and build our cities. Under the oceans, the crust is only about 3 miles thick. Under the continents, it can be about 25 miles thick. The mantle is below the crust and is about 1,800 miles thick. Parts of the mantle are so hot that rock flows slowly like thick honey.

The Core

The outer core is a layer of liquid metal, mostly iron and nickel. It is about 1,400 miles thick and incredibly hot. The spinning liquid metal creates Earth's magnetic field. The inner core is a solid ball of metal at the very center. It is about 1,500 miles across and can reach temperatures of 10,800 degrees Fahrenheit.

Fun Facts

• The deepest hole ever drilled only went about 7.5 miles down, not even through the crust.
• The inner core is as hot as the surface of the Sun.
• If the Earth were the size of an apple, the crust would be thinner than the apple's skin.

Did You Know?

Scientists have never actually seen the Earth's core. They figured out what it looks like by studying how earthquake waves travel through the planet. Different layers bend the waves in different ways!