Question

The total energy output of the Sun (its “luminosity”) is 3.826 ́ 1026Watts.

(a) How much energy is received on one square meter of the surface of Mars when the Sun is directly overhead (Mars is 2.3 ́ 108 km from the Sun)?

(b) This 1 meter square area absorbs one-quarter (0.25) of this Solar energy (reflecting or scattering the rest back into space). As a result it heats up until it emits exactly the amount of absorbed energy as infrared light. After that this piece of the surface of Mars is in temperature equilibrium, and stays at a constant temperature, balancing heating from the Sun with cooling by IR emission. If the emission process is that of a blackbody then what is the surface’s equilibrium temperature?

Answer 1