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.

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Answer 2

WHY IS THE SKY BLUE?

The blue color of the sky is due to Rayleigh scattering. As light moves through the atmosphere, most of the longer wavelengths pass straight through. Little of the red, orange and yellow light is affected by the air.

However, much of the shorter wavelength light is absorbed by the gas molecules. The absorbed blue light is then radiated in different directions. It gets scattered all around the sky. Whichever direction you look, some of this scattered blue light reaches you. Since you see the blue light from everywhere overhead, the sky looks blue.

As you look closer to the horizon, the sky appears much paler in color. To reach you, the scattered blue light must pass through more air. Some of it gets scattered away again in other directions. Less blue light reaches your eyes. The color of the sky near the horizon appears paler or white.

Answer 3

The cause is Rayleigh scattering. The atmosphere has a lot of small dust particles distributed throughout. When sunlight enters the atmosphere, the longer wavelengths of light (red light) literally "step over" these particles and continue on their way. Shorter wavelength (blue light) hit these particles and bounce off. Enough of the scattered blue light comes toward the surface so that we see the sky as blue.

Note that this is the same mechanism that causes red sunsets. The angle at which the sunlight comes towards us at sunset means that it is going through more atmospheric dust. Therefore, more and more blue light is scattered away from our eyes and only the red light can get through.

Answer 4

The sky is a mixture of many different colors created by the waves and particles that are constantly moving in space. the sky appears blue because the human eye can only see certain frequencies of waves and when you look at the sky you only see blue.

Answer 5

Because during the day the sky absorbs everything but blue light BILL NYE THE SCIENCE GUY

Answer 6

It is caused by rayleigh scattering, and the two explanations given in the answers are good ones. It is not caused by a reflection of the ocean! When I catch the high school science teachers that are teaching that...

Answer 7

the sky is not blue, its the reflection of the ocean.

Answer 8

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

Answer 9

Lets start from our eyes in day...
we see transparency around...

now we talk about nights...
its dark around...

so the mixture of this makes grey color and which is very near to blue...

Answer 10

beacuse of the air parricles and such in the air from light reflecting