Make a very rough estimate of the thermal energy content of Earth, assuming that the core has radius 3480 km, temperature 4000 K, density 11000 kg/m³ and heat capacity 800 J/K kg, and that the rest of the planet, dominated by the mantle, has radius 6370 km, temperature 2000 K, density 4500 kg/m³ and heat capacity 1200 J/K kg. Numbers for a more detailed model of the planetary interior can be found in the appendices to [212].