The colours are already there are components of visible light, the molecules in the atmosphere scatters the blue light mostly to create the blue appearance of the sky.

http://home.att.net/~RTRUSCIO/SPECTRUM.htm

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The Heavens Declare the Glory of Mathematics

Nice. Neptune is interesting because no one, apparently, knows why it is a deeper blue than Uranus. The only explaination so far seems to be due to a chromophore within the atmosphere of Neptune. [I haven't researched it much, however.]

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

From that link:

I would agree that it is concise, but it doesn't really say what causes the colors.

Well.......
Color is simply a perception generated within the brain. The parameters which cause the brain to present color as you see it are often quantified in three categories: hue, saturation, and brightness. The signal the brain receives is caused by the reaction of three types of color cones within your eye. These are typically called the red, green, and blue cones. You have about 6 million of these things in each eye.

These cones will respond differently for different colors of light that impacts them. For example, the more blue light that enters the eye, the more active are the blue cones, etc. Thus, the more blue we perceive.

You can think of light as being a wave or a particle, or both. In this case, I like the particle approach. When energetic atoms emit photons, these photons will have a fixed amount of energy depending on how and where they were emitted. The higher energy photons react much more often with the blue cones, and the lower energy photons react much more often with the red cones. Photons which are higher or lower outside of the visible range do not react in a way that allows any color detection. The energy range for these photons is really quite small. The entire range of energy for photons is called the spectrum and the range where the eye can see them is called the visible spectrum.

It is reasoned that evolution has caused eyes of all species to take advantage of this visible range of light because that just happens to be the bulk of the light that comes from the sun.

The sun produces, essentially, photons of every energy level you can imagine within and near the visible spectrum. The intensities (photons per second, or flux) for each energy level of photon varies somewhat in the visible spectrum. [The peak output of the sun is in the blue (not yellow as some would say).] Yet, the sun produces so much intensity of photon flux at all energies within the visible spectrum that it excites our color cones to their maximum reaction rate. This causes us to see white. Since clouds reflect all the photons almost equally, guess what color the clouds are? This is essentially true of the Moon, too.

Sunlight, or other sources of light, will bounce or scatter off surfaces. Some surfaces absorb photons within a certain range of energy levels, yet they will reflect other energy levels. A red apple will absorb the blues and greens and reflect mostly the "red" photons. Thus an apple appears red. Water is more the opposite, it absorbs more of the reds and produces a blue ocean instead.

In summary, there are three important elements to color. The source of light (what colors are being emitted), the objects properties of reflectance, and the response characteristics of our eyes (or eyes/brain, sometimes called the retinex). They all contribute to the wonder of color.

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

That's all fine and good, but ArgoNavis' post had a link that he implies explains why Jupiter's clouds have colors that orange, brown, etc. However, the link actually says that astronomers are hard pressed to explain the colors, as they should be colorless at the cool cloud temperatures, and only offers up two hypotheses. So, perhaps concise, but not definitive.

Yes, that is obvious. Ironically, I was being rushed to leave and missed that obvious point, yet I did a lengthy, time consuming explanation instead. This isn't far from par for me.

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

It's an old problem. Pascal, Twain, St Augustine and others are all credited with a quotation along the lines of: "I apologize for the length of this letter; I did not have time to write a shorter one."

Grant Hutchison

Thanks for some egg cleanser. I had forgotten that quote from Twain, though it is cool to here these other greats used it, too.

It is surprising how many great quotes are quite old. I recently read of Kepler when he stated: "not to throw the baby out with the bath water".

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

The sky is blue because the Magratheans have not yet emerged from their deep freeze to offer us custom made luxury planets

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The impossible often has a kind of integrity which the merely improbable lacks.

Can you please explain what you mean by the "Magratheans" ? Who or what are these ?

It's a reference to "The Hitchhiker's Guide to the Galaxy," in which there was a civilization called the Magratheans who build custom planets to order.

I was reading this page when I came across this explaination for the blue sky:
http://amasci.com/miscon/miscon4.html#blu
What he says seems to make some sense, that air is blue in large amounts like water is blue in large amounts. But I lack the understanding in physics to know if he's a nut case or a genius.
Anyone else who knows more than I (that would be most everyone here) care to enlighten me to this explaination please?
Thanks

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So many things I think about when I look far away,
Things I know, things I wonder,
Things I'd like to say. - RUSH - Mystic Rythums

I don't think I know more than you, but it seems like baloney to me:He doesn't come right out and say that he disagrees with the idea of scattering--he seems about to assert that each individual molecule would produce the scatter and show a "powdery blue" but he doesn't really go that far.

So an animal like an Eagle, which has much sharper vision than a human eye would these creatures see the sky as violet ?

I agree, and it is misleading. This statement of his alone does little to eschew obfuscation.

The color of objects that we normally see is due to the product of the spectral irradiance incident upon the object and the spectral reflectance properties of the object. A red lazer will reflect brightly off red objects and dimly off non-red objects.

It is different, however, when the particles that light is traveling through are smaller in diameter than the wavelength of light. Brucke first discovered this and Tyndall confirmed it with his great work. Air molecules, aerosols, dust, ash, smoke, some smog and other particles less than the wavelength of visible light cause Rayleigh scattering. This scattering gives great advantage to the blue end of the spectrum as the "blue" light will scatter about 9x more than the "red" light. Thus, we see more blue than any other color.

He is correct about seeing white if more atmospheres are involved since more scattering takes place and the blue light gets scattered away from us. Just how white it would be is likely horribly complex to determine. Mie scattering also enters the picture for light near the horizon.

Maybe. Many birds have tremendous color vision since they not only have four color cones, to our three, but their cones do not overlap each other in response.

However, the Sun is not all that bright in violet. Also, violet will scatter more often than blue, so it will scatter away through less atmosphere.

Then there is the issue of what the brain decides to do with all the color information, that is unknown, I think, for birds.

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

Hmm..

So ...why is the ocean color blue too?

Does it because it reflects the color of the sky?

Water has the property of absorbing more red light than blue. Air does not absorb much visible light. Reflection of a blue sky will improve the blue appearance, but the main answer for blue water is absorption.

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.

Many people tend to overthink this question. The answer is much simpler and funnier than most people would guess.

http://www.why-is-the-sky-blue.tv/wh...e-sky-blue.htm

Why is the grass green is another question that calls for a silly answer.

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Why Is The Sky Blue

Tell me why the stars do shine,
Tell me why the ivy twines,
Tell me what makes skies so blue,
And I'll tell you why I love you.

Nuclear fusion causes stars to shine,
Tropisms induce the ivy to twine,
Tyndall-Rayleigh scatter makes the sky look blue,
Testicular hormones are why I love you


(with apologies to Asimov)

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http://darksky.org/

As far as education goes, it's counterproductive to give an advanced answer to an introductory level question.

The sky is blue because air is blue.

Solids have color, liquids have color, and gasses have color.