In: Mechanical Engineering
The energy flux of solar radiation arriving at Earth orbit is 1353 W/m2. The diameter of the sun is 1.39x109 m and the diameter of the Earth is 1.29x107 The distance between the sun and Earth is 1.5x1011 m.
(a) What is the emissive power of the sun as calculated from the parameters given above?
(b) Approximating the sun’s surface as black, what is its temperature (as calculated from the parameters given above)?
(c) At what wavelength is the spectral emissive power of the sun a maximum?
(d) Assuming the Earth’s surface to be black and the sun to be the only source of energy for the earth, estimate the Earth’s surface temperature. Assume that the Earth absorbtivity to solar irradiation is 0.7. The actual average temperature of the Earth is currently ~288 K. Why do you think there are differences between your prediction and the actual average temperature (assume that the given value of absorbtivity is correct)?