Question

Assuming the Sun radiates as a blackbody at a temperature of 5800 K, calculate the expected surface temperature of the Earth, assuming that the Earth also acts as a perfect blackbody. Assume the Earth absorbs an amount of energy proportional to its cross-sectional area, but radiates as a spherical blackbody. If the Earth is in thermal equilibrium with outer space, then the energy received (mostly at visible wavelengths) must equal the amount of energy re- radiated (mostly) in the infrared. Assume an albedo value of 0.30 for the Earth. The albedo value is the fraction of the incoming visible light energy which gets reflected back to space.

The total power given by: ?(?) = ??^4 where ? = 5.67 × 10^−8 W. m^−2. K^−4

Answer 1