Fun facts about the outer core

Earth’s outer core is a layer of mostly liquid iron and nickel beneath the solid mantle and around the solid inner core. It begins roughly 2,900 kilometers below the surface and extends to the inner-core boundary.

How it works

Heat and composition-driven motion in this electrically conducting liquid help generate Earth’s magnetic field through the geodynamo. Seismic waves provide evidence that the outer core is liquid because some shear waves do not pass through it.

Example or application

The outer core is extremely hot and under enormous pressure. Its motion and interactions with the inner core and mantle are studied using seismic observations and geophysical models.

Scope and limits

Exact temperatures and compositions are estimates, not direct samples. Earth’s deep interior cannot be observed in the same way as surface rocks.

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