The sky is blue partly because air scatters short-wavelength light in preference to longer wavelengths and also because of density fluctuations in the moving air (see below). Combined, these effects scatter (bend away in all directions) some short, blue light waves while allowing almost all longer, red light waves to pass straight through. When we look toward a part of the sky not near the sun, the blue color we see is blue light waves scattered down toward us from the white sunlight passing through the air overhead. Near sunrise and sunset, most of the light we see comes in nearly tangent to the Earth's surface, so that the light's path through the atmosphere is so long that much of the blue and even yellow light is scattered out, leaving the sun rays and the clouds it illuminates red, at sunrise and sunset.
Scattering and absorption are major causes of the attenuation of radiation by the atmosphere. Scattering varies as a function of the ratio of the particle diameter to the wavelength of the radiation. When this ratio is less than about one-tenth, Rayleigh scattering occurs in which the scattering coefficient varies inversely as the fourth power of the wavelength. At larger values of the ratio of particle diameter to wavelength, the scattering varies in a complex fashion described, for spherical particles, by the Mie theory; at a ratio of the order of 10, the laws of geometric optics begin to apply.
Individual gas molecules are too small to scatter light effectively. However, in a gas, the molecules move more or less independently of each-other, unlike in liquids and solids where the density is determined the molecule's sizes. So the densities of gases, such as pure air, are subject to statistical fluctuations. Significant fluctuations are much more common on a small scale. It is mainly these density fluctuations on a small (tens of nanometers) scale that cause the sky to be blue.
2006-08-23 09:55:27
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answer #1
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answered by cherry 3
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The blueness you see everywhere else is all of the atoms in the atmosphere scattering blue light toward you. (Because red light, yellow light, green light and the other colors aren't scattered nearly as well, you see the sky as blue.)
2006-08-23 16:49:49
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answer #2
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answered by Just Curious 1
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When light hits the atmosphere, air, dust particles, etc. scatter it. Blue is the shortest, highest-energy wavelength and is therefore diffused the most.
2006-08-23 16:53:19
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answer #3
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answered by Emily I 2
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casue apples r red
da grass is geen
bananas r yellow
grapes r purple
ect.
n there was nothin important dat was blue
so thats why the sky is blue
lol
2006-08-23 16:52:44
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answer #4
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answered by Anonymous
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because we say so. If blue were called purple then the sky would be purple
2006-08-23 17:00:47
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answer #5
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answered by DeeLicious 4
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its not blue its black. the light from the sun turns it blue.
2006-08-23 16:52:25
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answer #6
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answered by Morrie 2
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There is a person which can answer your question perfectly: RAYLEIGH.
2006-08-24 04:23:20
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answer #7
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answered by kollado69 1
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Why do people ask this question almost every day?
2006-08-23 16:58:18
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answer #8
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answered by Anonymous
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because God made it that way.
2006-08-23 16:51:23
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answer #9
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answered by DisneyLover 6
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yeah....pfft......god made it that way. brilliant.
2006-08-23 16:52:17
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answer #10
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answered by Anonymous
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