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Blue Skies

Environment, Perceptions, Science and Technology

As many of you know, some much to their disgust, I happen to believe in Creation, or "intelligent design" if you prefer. I have written extensively about this in a prior post  ("In the Beginning ...") and so will not revisit that argument. But it has struck me for some time that our world is filled with beauty, mainly in the form of color. Grass and foliage are luscious green, flowers are every color and shape under the rainbow and then, of course, there is the rainbow. Birds vary in plumage from relatively dull to the brilliant hues of Cardinals, Goldfinches and Bluebirds. Goldfinches even change from a boring dull green in winter to their brilliant black and gold heraldry of spring.

The riot of color bestowed on us by flowers defies description. Literally every color under the sun (except maybe black which technically is no color at all) is represented, from majestic roses to the lowly dandelion. Many birds sport plumage of brilliant color. Even the lowliest of creatures often are beautiful in their own way.

Have you ever thought what a dull, drab world it would be without the gift of color? Even the sky is blue, a miraculous gift covering the blackness of space. Also, have you wondered why? After all, beauty really serves no practical purpose. Plumage is often explained as serving to attract the opposite gender, but then how about the rather mundane such as the starling, brown sparrow or even the little gray mouse? Are they doomed to frustration and extinction? No, that can't be the whole story. Flowers are virtually a limitless panoply of brilliant hues and shapes. It can't all be just to attract bees. In fact, most animals are color blind and see only in black and white. So how does this all come to be and why? Aye, there is the miracle.


Take the sky, a brilliant blue when weather permits. Some of you may have been taught that it has to do with dust particles in the air filtering the light. Sorry, science teacher, that's wrong. In fact it's implausible because dust particles vary in size and so would not result in a consistent blue. Actually, molecules of nitrogen, a fortuitously major component (81%) of the atmosphere, form the filter.

Nitrogen and oxygen molecules, which make up 98% of our atmosphere, are of a diameter that is less than the wavelengths of visible light colors. These molecules are much smaller in diameter--less than 1/1000th--than the wavelength of blue light, so they scatter that wavelength via a mechanism called Rayleigh scattering.  The scattering effectiveness varies with the fourth power of the wavelength, so blue light is scattered 10 times more effectively than red. This scattering effect renders the sky blue to our eyes while still letting all the color wavelengths*, including blue, through.  (Actually, violet is scattered even more effectively, but our eyes are much less sensitive to violet so we just see the blue.)

*NOTE: Light is technically not a wave phenomenon, but rather a quantum radiation involving energy packets. That's so mathematically complex that scientists still use the wavelength concept for light because it works in most cases and is much easier to employ. We'll stick to wavelengths.

Sunsets are often red because the longer and lower light path from the sun near the horizon increases the effect of dust particles and water droplets, which are larger and scatter more red light.

The net result of all this scientific stuff is a beautiful blue (or red or orange) sky instead of the depressing blackness of space. What a lucky happenstance--or not.

Bird and flower colors are created differently. The pigments that create their colors contain tiny particles that selectively reflect and absorb certain colors. What we see are the reflected color wavelengths. (This same process is used in print and paint pigments.)

Even the night sky is decorated with stars and the brilliant shape-changing moon. The net result is an interesting and beautiful night sky decorated with countless tiny sharp lights and one large one rather than just featureless blackness. Occasionally we even get meteor showers and the northern lights added in to further delight us.

The bottom line is we are surrounded by beauty, little of which has a practical purpose except to entertain and delight us poor humans. We virtually alone (maybe alone--I haven't researched this) have eyes with the retinal detection range to see it all. If only we take some time and open those wonderful eyes to the gift of nature's palette all around us. Please do, and enjoy a truly beautiful world.

God's a pretty nice guy after all, isn't he? 

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