The paper we discussed in the latest meeting of Magnetic Personalities and which motivated the piece below was Anzellini et al. (2013; Science) “Melting of Iron at Earth’s Inner Core Boundary Based on Fast X-ray Diffraction”.

They estimate the temperature of the boundary between the inner and outer core to be around 6,000 degrees Celsius based on extrapolations of the melting temperature of iron at extreme pressures and temperatures. Extrapolating from this, the top of the core would be just under 4,000°C and the heat flow to the base of the 1,000°C cooler mantle some 10 TW. For comparison, this transfer of energy is just under the 13TW present rate of energy “consumption” (energy is never consumed, only transferred and transformed) by all of human civilisation.