Solar Brightness on Moon Compared to Earth
Name: Doug S.
I have heard a casual comment that the moon receives
20 times as much light as the earth does, due to the lack of an
My question has to do with relative apparent brightness, if a person was
standing on the moon compared to the earth. Also, given that the moon
has no atmosphere, would there not also be an immediate extreme risk of
eye damage due to far higher UV and infrared light on the moon?
The "insolation" (the amount of light from the Sun impinging upon an
interstellar object) of the Moon and Earth would be similar if the
detector is above the Earth's atmosphere, since the intensity in the
absence of an absorber decreases with distance, R, like 1/R^2. This
neglects fluctuations of the solar output, occultations, and the like. You
are correct that the Earth's atmosphere absorbs a significant amount of
ultraviolet and infrared radiation. In the absence of an atmosphere, there
is a risk of eye damage from ultraviolet, infrared, and even intense
visible light. In addition, there are solar "winds" in which streams of
particles (largely protons, electrons and alpha particles).
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Update: June 2012