How warm is moonlight?
from sopularity_fax@sopuli.xyz to nostupidquestions@lemmy.ca on 06 Oct 13:52
https://sopuli.xyz/post/34789440
from sopularity_fax@sopuli.xyz to nostupidquestions@lemmy.ca on 06 Oct 13:52
https://sopuli.xyz/post/34789440
what are its properties
#nostupidquestions
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Light does not have a temperature and thus is not warm.
If you mean the color temperature of moonlight, it is around 4000K. 4000K are neither a warm nor a cold color temperature but quite neutral. Compared to daylight it’s warm, and compared to warm light it’s cold.
Photons hitting things transfer their energy when they are absorbed, producing heat in the object hit
Exactly. This causes the object to become warm.
The other person is incorrect. The moon does reflect heat from the sun, but it is very weak and barely detectable on earth.
Why not just reply to the other person
Because OP asked for the answer
Because I wasn’t attempting to have a conversation with the other person. I don’t care to try change their mind. I was responding to OP.
The moon reflecting some radiation from the sun (some visible light and infrared radiation) does not affect the fact, that the the individual photons do not have a temperature.
Yeah, same as the sun. Photons hit us and interact with our matter thereby increasing our temperature. Moon and sun are only different in intensity at certain wavelengths and that the moons photons originate from the sun instead of being generated by the moon.
But I would interpret the original question as “how much energy does moon light contain” or “how much can moon light warm us”.
And somebody answered the question in regards to heating the whole earth here. For the whole earth it was something like 1 Millikelvin, so one thousand of a degree Celsius. So practically it can be ignored.
Let’s take average moonlight, so half the moon lit (Quarter or 3/4 phase) in the visible spectrum. That has an Exposure Value of about -4. Bright sunlight has an EV of about 16. So the difference is around 20 “stops” (a photography term that means twice as bright in absolute terms - but visually we barely notice a difference of a stop or two, eyes just adjust.)
Since EV and stops are based on powers of 2, 20 of them means moonlight is about a millionth as strong at illuminating things as sunlight.
I assume heating power is very similar (most of the energy from the sun that heats surfaces on earth is actually in the visible light, not the infrared anyway)