It's not easy being green

Rick posted:
Sure looks pinkish/peachy to me.

Well, the analysis is somewhat strange. In particular from that website, "It
has to be emphasized that white is a relative thing, at least to a certain
extent. It is relative to the D65 white that the Sun is peachy pink. Item 16
of the Color FAQ states that for most people D65 has a little hint of blue. So
maybe the Sun is really white?"

Again, through large telescopes, early G-class main sequence stars have very
little color to them. Most star colors are fairly pastel anyway. The
G-giants like Capella are slightly yellowish in color to the eye, and by the
time you get to K-class stars, the yellow color is fairly obvious. One color
contrasting pair is Alberio (Beta Cygni) with a pretty almost golden primary
star sitting next to a pale bluish companion. Clear skies to you.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

**********************************************
* Attend the 10th Annual NEBRASKA STAR PARTY *
* July 27-Aug. 1st, 2003, Merritt Reservoir *
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"Rick" wrote in message...
...

"David Knisely" wrote in message ...

Rick posted:

Then how do you account for the myriad shades of orange, like
our own sun which supposedly is a pinkish/peachy/orangey blend
of red and yellow when seen from 1 LY away?

The sun's total color is more an off-white than any particular color. There
are many examples of stars similar to the sun in the night sky (Alpha
Centauri-A, Tau Ceti, ect., and none look "pinkish/peachy/orangy".

Ok, I was taking the info from he
http://casa.colorado.edu/~ajsh/colour/Tspectrum.html
http://www.vendian.org/mncharity/dir...color/sun.html
and referenced links.

Sure looks pinkish/peachy to me.

Rick

'Lo Rick --

Stars that are blends of color are more similar, say in
temperature, to stars that are nearer to being primary
colors?

yellow orange red

....these are not the huge leaps that

yellow green blue

would be...

So while a red star is not so much different than a
yellow star, a blue star is quite a bit hotter than the
yellow star... so there is no "in-between" green star.

hthy

happy days and...
starry starry nights!

--
"Oh give me please the Universe keys
That unlock all those mysteries!"
You pay your fees, you find some keys
That keeps you always groping.

"Oh give me please the Happiness keys
That ease the pain of biting fleas!"
Today you seize you need no keys,
That door is always open.

Paine Ellsworth

"Rick" wrote in message...
...

"David Knisely" wrote in message ...

Rick posted:

Then how do you account for the myriad shades of orange, like
our own sun which supposedly is a pinkish/peachy/orangey blend
of red and yellow when seen from 1 LY away?

The sun's total color is more an off-white than any particular color. There
are many examples of stars similar to the sun in the night sky (Alpha
Centauri-A, Tau Ceti, ect., and none look "pinkish/peachy/orangy".

Ok, I was taking the info from he
http://casa.colorado.edu/~ajsh/colour/Tspectrum.html
http://www.vendian.org/mncharity/dir...color/sun.html
and referenced links.

Sure looks pinkish/peachy to me.

Rick

'Lo Rick --

Stars that are blends of color are more similar, say in
temperature, to stars that are nearer to being primary
colors?

yellow orange red

....these are not the huge leaps that

yellow green blue

would be...

So while a red star is not so much different than a
yellow star, a blue star is quite a bit hotter than the
yellow star... so there is no "in-between" green star.

hthy

happy days and...
starry starry nights!

--
"Oh give me please the Universe keys
That unlock all those mysteries!"
You pay your fees, you find some keys
That keeps you always groping.

"Oh give me please the Happiness keys
That ease the pain of biting fleas!"
Today you seize you need no keys,
That door is always open.

Paine Ellsworth

Rick wrote:

Is that why most plant material on Earth is green, to absorb the
widest range of solar energy?

Green plants contain chlorophyll, which looks green because it
absorbs nearly every visible frequency *but* green, so it picks up
the 'shoulders' of the peak rather than the central portion. Its
strongest absorption, though, is towards the blue end of the
spectrum, where individual photons have the most energy.

See http://tinyurl.com/n891.

I believe that the ability of chlorophyll to convert radiant energy
to available electrochemical energy is a more important property than
the exact frequency range it absorbs, although of course it wouldn't
be much use if those frequencies weren't near the peak in the solar
spectrum. A pigment that absorbed strongly over the whole visible
spectrum would appear black.

--
Odysseus

Rick wrote:

Is that why most plant material on Earth is green, to absorb the
widest range of solar energy?

Green plants contain chlorophyll, which looks green because it
absorbs nearly every visible frequency *but* green, so it picks up
the 'shoulders' of the peak rather than the central portion. Its
strongest absorption, though, is towards the blue end of the
spectrum, where individual photons have the most energy.

See http://tinyurl.com/n891.

I believe that the ability of chlorophyll to convert radiant energy
to available electrochemical energy is a more important property than
the exact frequency range it absorbs, although of course it wouldn't
be much use if those frequencies weren't near the peak in the solar
spectrum. A pigment that absorbed strongly over the whole visible
spectrum would appear black.

--
Odysseus