> Light value is proportional to the square of diameter of the light source.
> The half moon is half a circle with the same diameter as a full moon, thus
> half the light. If a half moon was a circle one-half the diameter of the
> full moon, then it would yield 1/4 the light.
>
> Like other electromagnetic radiation, light obeys the "square law," as it
> falls off with the square of distance, which might be what you're thinking
> of. But the half moon is still about the same distance from us as the full
> moon... :-)
Thanks for the replies. I've been working away for this week.
I get it now. The distance is constant, but the amount of light is halved.
If the moon moved back by a factor of 2 when it was full would cause a loss
in light to 1/4. And some strange tides. If any.
Foxy
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