Energetics of core formation

The loss of gravitational energy on core formation is calculated for the case of simple unmixing of two components, whose equations of state are found from the present density distribution. Without allowance for thermal expansion, the mean energy available for heating is 600 cal/g; with an approximate allowance for thermal expansion, this is reduced to 400 cal/g, which is equivalent to a mean rise of temperature of about 1600°. The moment of inertia of the undifferentiated earth is found to be about 10% greater than that of the present state, for the spherical model.