[sci.astro] The Color of the Sun

michaelm@bcsaic.UUCP (03/05/87)

In article <467@cfa.cfa.harvard.EDU> wyatt@cfa.harvard.EDU (Bill Wyatt) writes:
>What you say is correct, but be careful here - I'd say the main reason
>the Sun seems white is that we (and our eyes) evolved under its
>illumination - of course it seems the most balanced color! (i.e. white).

This was the first thing that occurred to me.  But I wonder--in the average
scene, how much of the lighting is contributed directly by the sun (i.e. from
the 1/2 degree across area the sun covers), and how much by the remainder of
the sky (blue or clouded)?  Note also that our eyes adapt their color
sensitivity to the prevailing illumination--if you're walking in a green
forest where you can't see the sky, so your illumination is highly filtered by
the green foliage, you still perceive colors fairly accurately.  (What was red
in plain daylight still is, etc.)  If you glimpsed the sun under those
circumstances, what color would it appear?  In other words, white is highly
relative to the prevailing illumination; if your main light source is from the
sun, then it probably looks white to you.

Please note that I'm cross posting to sci.bio.
-- 
Mike Maxwell
Boeing Advanced Technology Center
	arpa: michaelm@boeing.com
	uucp: uw-beaver!uw-june!bcsaic!michaelm