The sky is blue partly because air scatters short-wavelength light in preference to longer wavelengths. 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.
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.
Why is the sky blue instead of violet?
Because of the strong wavelength dependence (inverse fourth power) of light scattering according to Raleigh's Law, one would expect that the sky would appear more violet than blue, the former having a shorter wavelength than the latter. There is a simple physiological explanation for this apparent conundrum. Simply put, the human eye cannot detect violet light in presence of light with longer wavelengths. There is a reason for this. It turns out that the human eye's high resolution color-detection system is made of proteins and chromophores (which together make up photoreceptor cells or "Cone" structures in the eye's fovea) that are sensitive to different wavelengths in the visible spectrum (400 nm–700 nm). In fact, there are three major protein-chromophore sensors that have peak sensitivities to yellowish-green (564 nm), bluish-green (534 nm), and blue-violet (420 nm) light. The brain uses the different responses of these chromophores to interpret the spectrum of the light that reaches the retina.
When one experimentally plots the sensitivity curves for the three color sensors (identified here as long (L), middle (M), and short (S) wavelength), three roughly "bell-curve" distributions are seen to overlap one another and cover the visible spectrum. We depend on this overlap for color sensing to detect the entire spectrum of visible light. For example, monochromatic violet light at 400 nm mostly stimulates the S receptors, but also slightly stimulates the L and M receptors, with the L receptor having the stronger response. This combination of stimuli is interpreted by the brain as violet. Monochromatic blue light, on the other hand, stimulates the M receptor more than the L receptor. Skylight is not monochromatic; it contains a mixture of light covering much of the spectrum. The combination of strong violet light with weaker blue and even weaker green and yellow strongly stimulates the S receptor, and stimulates the M receptor more than the L receptor. As a result, this mixture of wavelengths is perceived by the brain as blue rather than violet.
You could get more information from the link below...
2006-12-17 22:49:50
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answer #1
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answered by catzpaw 6
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ok, normal light is known as "white light" but white light is made up of the primary colours red, blue and yellow when the sun is fully in the sky the particles in the atmosphere reflect the red and yellow colours away from the earth and allow the blue light through. but when the sun is rising or setting the particels in the sky reflect the light diferently therefore letting the red and yellow colours threw and reflecting the blue away. it's confusing but i hope that helps.
2006-12-17 23:11:10
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answer #2
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answered by Anonymous
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Why is the sky blue?
A clear cloudless day-time sky is blue because molecules in the air scatter blue light from the sun more than they scatter red light. When we look towards the sun at sunset, we see red and orange colours because the blue light has been scattered out and away from the line of sight.
The white light from the sun is a mixture of all colours of the rainbow. This was demonstrated by Isaac Newton, who used a prism to separate the different colours and so form a spectrum. The colours of light are distinguished by their different wavelengths. The visible part of the spectrum ranges from red light with a wavelength of about 720 nm, to violet with a wavelength of about 380 nm, with orange, yellow, green, blue and indigo between. The three different types of colour receptors in the retina of the human eye respond most strongly to red, green and blue wavelengths, giving us our colour vision.
2006-12-17 23:05:32
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answer #3
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answered by ticklemeblue 5
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THE SKY IS NOT BLUE BECAUSE OF THE REFLECTION OF THE OCEAN!!!!!
come on people, leave your ignorance at the door.
2006-12-17 23:03:57
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answer #4
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answered by Mr. Charles 3
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The sky is blue because of the reflection of the ocean
2006-12-17 23:02:41
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answer #5
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answered by mark k 1
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Due to Rayleigh scattering of light from small molecules in the air.
Also see Mie scattering, a product of our pollution and small particles.
http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html#c4
2006-12-17 23:08:34
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answer #6
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answered by Anonymous
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Reflection of oceans (large surface area of Earth) on the outer atmosphere... not forgetting colours are a human invention as perceived and interpreted by the brain!
2006-12-17 23:03:57
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answer #7
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answered by waynebudd 6
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Rayleigh scattering.
2006-12-17 23:08:23
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answer #8
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answered by Stephen McNeil 4
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because of the light from the sun entering the atmosphere makes it look blue. i think XD
2006-12-17 23:02:12
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answer #9
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answered by Anonymous
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because of the reflection and refraction of light in the atmosphere.
2006-12-17 23:41:19
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answer #10
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answered by Anonymous
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