Planets - Effective Temperature vs Actual Temperature


by ExcessRed
Tags: actual, effective, planets, temperature
ExcessRed
ExcessRed is offline
#1
Jun9-11, 04:08 PM
P: 16
Why is the actual mean temperature of the moon so much lower than the effective temperature?

NASA lists the effective temperature of the moon at 270.6 kelvin.
The mean temperature of the moon at the equator is 220 kelvin.
With no atmospheric effects, why is the surface temperature so much lower than the effective temperature predicts?

Rephrasing for clarity:
What factor is NOT part of the effective temperature formula that so dramatically affects the actual temperature of the moon?

Normally one would say atmospheric effects, but the moon effectively has no atmosphere - certainly not enough of one to cause this big of a discrepancy.
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Vagn
Vagn is offline
#2
Jun9-11, 05:01 PM
P: 286
Quote Quote by ExcessRed View Post
Why is the actual mean temperature of the moon so much lower than the effective temperature?

NASA lists the effective temperature of the moon at 270.6 kelvin.
The mean temperature of the moon at the equator is 220 kelvin.
With no atmospheric effects, why is the surface temperature so much lower than the effective temperature predicts?

Rephrasing for clarity:
What factor is NOT part of the effective temperature formula that so dramatically affects the actual temperature of the moon?

Normally one would say atmospheric effects, but the moon effectively has no atmosphere - certainly not enough of one to cause this big of a discrepancy.
I think Albedo, i.e. how much of the radiation is reflected by the body, is ignored when calculating the effective temperature.
ExcessRed
ExcessRed is offline
#3
Jun9-11, 07:59 PM
P: 16
Actually, the two formulas I have seen that determine the effective temperature use albedo as a factor - I should have mentioned that.

I have to plug in an albedo of around .34 for the moon to come up with an effective temperature of 220, whereas the moon has an albedo around .11


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