The solar flux density (amount of energy coming from the Sun) at the radius of the Earth’s orbit is 1.38 × 10³Wm^－2. A major internal heat source for Earth today is radiogenic heating and this, as you may recall from Chapter 2, provides a flux of 5 × 10^－12Wkg^－1. Calculate the total power from the Sun and from radiogenic heating for the Earth and compare the two values. Use the values given in Appendix A, Table A1 for the mass and radius of the Earth.