Earth's Layer

Crust

This is the layer we live on! It is the earth's outermost and thinnest layer, only a few miles (5 km) thick u nder the oceans and averaging 20 miles (30 km) thick under the continents.

The crust is one of the chemically different layers and is composed mainly of oxygen, silicon, and aluminum. The continental crust is similar to granite, while the oceanic crust is composed primarily of basalt.

Mantle

The largest layer by volume, the mantle is ~2900 km thick.The mantle is broken into 2 layers: upper and lower mantle. The upper layer is contained within the lithosphere and is a brittle solid, while the lower mantle is a hot, semi-solid crystal mush that behaves plastically when deformed.The mantle is one of the chemically different layers and is composed entirely of the rock peridotite which contains abundant iron, magnesium, and silicon.

Inner Core

An extremely hot, solid sphere of mostly iron and nickel at the center of the earth. It is 5,150 to 6,378 km below the surface and about 1,200 km in diameter. Temperatures are hot enough for the inner core to be molten, however the extremely high pressure forces it to be solid.

Outer Core

The outer core is the only liquid layer of the earth – composed mostly of iron and nickel. It is roughly 2,890 to 5,150 km below the surface and about 2,300 km thick. The liquid that makes up the outer core is constantly moving in a process called convection, which produces our magnetic field.

Asthenosphere

The plates of the lithosphere move (or float) on this hot, malleable semiliquid zone in the upper mantle, directly underneath the lithosphere. The asthenosphere behaves like a plastic when deformed and is one of the mechanically different layers of Earth.

Lithosphere

Made up of the crust and a bit of upper mantle, this layer is divided into several constantly moving plates of solid rock that hold the continents and oceans. The lithosphere is one of the mechanically different layers and is a brittle solid which will fracture or break when deformed.

Core

The core is one of the chemically different layers of the Earth and is composed almost entirely of iron and nickel, making it the densest layer by far. It is also broken into two different mechanically different layers: the inner core and outer core.