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Geophysics & Environmental Physics

Earth's Outer Core

The fluid interior layer of Earth ~2,260 km thick composed of liquid iron-nickel alloy surrounding the solid inner core.

Governing formula Radius ~ 3480 km to 1220 km (Liquid Iron-Nickel Alloy)
SI unit Pa·s (Liquid Viscosity ~10⁻³ Pa·s)

In depth

S-waves cannot propagate through the liquid outer core (creating a seismic S-wave shadow zone). Thermal and compositional convection in this electrically conductive fluid powers the geodynamo that generates Earth's magnetic field.

Examples in the real world

Seismic S-wave shadow zones between 104° and 140° distance confirming the outer core is liquid.