and normal modes constrain the radius of the outer core to be 3483 km with an uncertainty of 5 km, while that of the inner core is 1220±10 km.

Estimates for the temperature of the outer core are about 3000 - 4500 K in its outer region and 4000 - 8000 K near the inner core. Modeling has shown that the outer core, because of its high temperature, is a low-viscosity fluid that convects turbulently.