why is sky blue?

Answer 1

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.

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Answer 2

The color we perceive is the result of absortion and non-absorption of the spectrum. Our atmosphere is made up mostly of nitrogen gas which absorbs all colors of the spectrum except the blue and violet. Actually, the color of our sky is nearer to the violet spectrum but since our eyes are more sensitive to blue, what we perceive is the blue color of the sky. The homogeneous color of the sky is due to the scattering of the light by water vapor, gases and dust so the sky looks somewhat uniformly blue.

Answer 3

I checked out the wikpedia site and it said it is PARTLY due to the diffusion of light particles...although I agree, I only partly agree ... I feel the main reason the sky is blue is due to the reflection of our blue ocean off the upper atmosphere... the atmosphere acts much like a mirror during day light... to prove this check out pictures of the sky on mars, its red like the planet... the atmosphere is like a bubble around the planet, when the bubble is back lit by the sun it creates a slight mirror effect...

Answer 4

No one above is correct!

For a detailed (and somewhat technical) answer, see http://en.wikipedia.org/wiki/Diffuse_sky_radiation

It has to do with the scattering of sunlight by particles in our atmosphere. Different colors are scattered by different amounts. You know the order of the colors of the rainbow - Red, Orange, Yellow, Green, Blue, (Indigo), Violet. Well, the red end of the spectrum gets scattered the least, and the violet (blue) end gets scattered the most. So the red, orange, and yellow light appears to stay close to the Sun (it doesn't get scattered much) and the rest of the spectrum scatters off the atmosphere particles back into our eyes, making the atmosphere look blue.

Why blue and not violet? Because the Sun doesn't emit much violet light, and our eyes are much more sensitive to blue than to violet.

Answer 5

The atmosphere absorbs all colors of the color scheme besides blue. Thus, the sky appears to be blue.

Answer 6

U should wear it with dark wash skinny jeans,gray jeans or black jeans. These would look best with a sky blue shirt

Answer 7

I think (so don't repeat this at fact) but I think it is because the light from sun reflects off water in atmosphere and is the color of blue!!!!????

Answer 8

Because that is the color that God chose for the sky, very simple!!!!

Answer 9

sun reflects blue light

Answer 10

R U 5 YEAR'S OLD