The fluid outer core surrounds Earth's solid inner core, and is made of iron, nickel, and smaller amounts of other metals. The movement of liquid iron in the outer core generates both electricity and magnetic fields. As the metal of the outer core flows through these fields, more electric currents and subsequent magnetic fields result. This entire self-sustaining system is called the geodynamo, and it forms the gigantic magnetic field that surrounds the Earth.
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Key Facts In This Video
Iron is the most stable element produced outside of a supernova. 01:46
As the Earth formed, denser materials such as iron and nickel worked their way to the center, while lighter materials stayed near the surface. 02:39
The metallic convection currents of Earth's outer core create its magnetic field, which shields the planet from solar wind. 03:42