(a) The Sun is a nearly perfect blackbody emitter (e 1) with a temperature of 5500 K and a radius of 7 10⁸ m. Determine the radiative power that the Earth receives from the Sun. The distance between the Earth and the Sun is 1.5 10¹¹ m and Earth's radius is 6380 km. (b) The temperature within the Earth's crust increases about 1C from each 30 m of depth. The thermal conductivity of Earth's crust is 0.80 W/(C m). Determine the thermal power transferred from Earth's interior to its surface (for the entire Earth).