Planetary Temperatures

Planetary Temperatures - Planetary Temperatures We can...

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Planetary Temperatures We can calculate the temperatures that we would expect the planets to have using some simple heat balance equations. The total energy received over the whole of a planet is given by the area it presents to the Sun times the radiation per square meter at that point. The radiation power per square meter at the earth is given by S, the solar constant (around 1360 W m -2 ), and we know S falls off according to the inverse square law. Hence energy received by planet: = (S/a 2 )[pi]R 2 where a is the distance from the sun in AU. Effective Temperature , T e : If a body and its atmosphere is at a uniform temperature T e , then it will emit as a black body radiator of effective temperature T e . Rate of emission = 4[pi]r 2 [sigma]T e 4 where [sigma] is Stefan's Constant. If we define the albedo as (Energy reflected)/(Total energy received), and call this A, then the total energy absorbed is given by: Total Energy Absorbed = [pi]R 2 S (1-A)/a 2 where a = a p /a e , and a p is the distance of the B>p is the distance of the planet from the sun in
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Planetary Temperatures - Planetary Temperatures We can...

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