Why is the 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.

You could get more information from the link below...

Answer 2

The size of blue light waves are such that they bounce off the nitrogen and oxygen atoms in the air more than other colors, SO, the light that comes out of the Sun that WOULD pass by over your head if it just traveled in a straight line gets bounced around by the N2 and O2 atoms. But mostly the blue light. The green, yellow gets scattered less, and the red hardly at all, it just "passes on through." So, you see the sky as blue because the scattered (blue) light comes down from overhead where the other colors don't.

This is the same reason the sunset is red. The blue light is scattered away (making someone ELSE's sky blue west of you) and only the red light passes straight through to you, making the sunset red.

Answer 3

Bcuz of all the particles in the sky. The light rays go through the particles and turn them blue. Thats y the sky is red at night, bcuz the sun goes down and shines on other particles! hope that helped.

Answer 4

as sunlight has to travel a long distance to reach earth,it has to pass through many dust and other particles in the space .so the sunlight undergo scattering.we know sunlight is a mixture of many colors having different ranges.blue color has longest range and red is the shortest.
so by scattering, blue color is scattered more b'coz of its range and we are seeing sky as blue.

Answer 5

I will agree with Emmanuel

nice name

um yeah Ask God
Its a cool color
at least its not green or yellow right

Answer 6

it's how the light bends when it enters the earth.

Answer 7

BECAUSE IT'S COLOUR IS BLUE

Answer 8

lol @ Emmanuel...

i wonder what our society would be like if everyone thought this way?

Answer 9

Because it is.

Answer 10

You would think I know the answer to this one...........