AW: color of sun
theresaw at oso.chalmers.se
Thu Feb 20 09:51:30 CET 2003
> Theresa Wiegert:
> >> Actually, the sun *is* yellow! It's classified as a G-star
> So if we make a spectral analysis of the sun it emits a little more
> electromagnetic radiation of wavelengths corresponding to yellow
> than of the other wavelengths. Is this visible with human eyes?
> Probably only from far away, let's say from Alpha Centauri.
Ah, nono. Of course you can't look directly into the sun when it's
daylight, it's far too bright (and you shouldn't!), but it's not white.
YellowISH, I should say. And it's the same yellow tone of light as when
you look at stars from far away. betelgeuse is red, Rigel is blue, Alpha
Centauri is yellow. (well, hard to say if it's the same actually, in
darkness, your cones (? the ones who are colorsensitive) tend to not be
very useful, and the lightsensitive (rods?) take over. Still, the
colordifferences are visible to you. So what we can do, to see how we
find the sun, is to take a paper, and make a hole with a thin pin, and
then gaze on the sun through it (not for long!!! just for a fraction of a
second, let the eye cross the plane of the sun quickly), or make an
eclipse using your finger to cover the sun instead of the moon, and see if
you can see the color of the corona. the same here, use extreme caution! I
don't want anyone to be blind or get damaged eyes (it IS very very
In any case, an astronomer always calls the sun yellow.
> In any case the sun is not as yellow as crayons - or comic book yellow.
No, but it's more accurate yellow than white, in any case. (just as water
is more accurate blue than purple for instance)
> Could it be that it looks more yellow near sunset, before it gets orange,
> then red and ultimately night falls? This would probably be due to diffraction
> of the sun's light in earth's atmosphere.
Yep. The shorter wavelengths get lost (blue), and the longer (red)
stays. But there has to be a great deal of pollution to make the sun red.
The sunsets and sunrises I can remember, it has always been more bright
> Another example: Water in small amounts (let's say in a bucket) is not
> nearly as blue as it is depicted in comic books. Water looks blue only if
> you have lots of it (like in an ocean).
...and if there's a blue sky above it getting reflected in it. Isn't
seawater more greenish otherwise?
> What I have always wondered is why Chinese (or Asian people
> in general) are depicted as yellow. In reality their skin color
> is not a little bit yellow. It is exactly like the skin color
> of Europeans.
Oh yes, that's a bigger conundrum!
Well, is it exactly like europeans, isn't it a wee bit darker, or rather,
europeans are almost colorless? (I am, for sure, during
wintertime, no pretty sight...)
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