Why is the sky blue?

Answer 1

It is because of scattering and diffraction. More blue light are being scattering.
The question had been asked before, many times over.
However, people are patiently answering it many times over.
That is nice.



he case was finally settled by Einstein in 1911, who calculated the detailed formula for the scattering of light from molecules; and this was found to be in agreement with experiment. He was even able to use the calculation as a further verification of Avogadro's number when compared with observation. The molecules are able to scatter light because the electromagnetic field of the light waves induces electric dipole moments in the molecules.
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.
Source(s):

Wikipedia.key word' sky', Why is the sky blue?
Original by Philip Gibbs May 1997.

Answer 2

It's not. It's purple...(Truly)


It is because of diffuse skylight radiation. Our atmosphere scatters the light that reaches us. Depending on the angle in which sunlilght hits the atmosphere, the light's wavelength shifts towards the blue spectrum or the red. That is why we have a blue sky during the day when the sun is above us, and why sunsets are red, when the light comes from the side. The reason the sky appears blue instead of purple, is that the human eye can not detect violet light when there is light with longer wavelength's present.

Answer 3

The blue color of the sky is due to something called Rayleigh scattering. As light passes through the atmosphere, most of the longer wavelengths go straight through. The longer wavelengths of light are red, orange and yellow. So, those colors of light zip right through. However, much of the shorter wavelength light (like blue) is absorbed by molecules in the atmosphere. This absorbed blue light is then radiated in all directions. Therefore, it gets scattered so that wherever you look some of this blue light reaches you. This makes the sky appear blue in daylight.
http://www.sciencemadesimple.com/sky_blue.html

Answer 4

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 5

this is an addition to Jerry P.- The Rayleigh scattering works just like the way a light bulb and its plastic cover works. The cover, which is ragged, scatters the light in all directions as oppossed to not having a cover then the light would be more focused on a smaller area.

Answer 6

What grade are you in? (The answer is a complicated one that involves physics- most students learn about it in high school physics class. It would help us to have an idea of what terms you might already know, ex. do we need to explain diffusion and diffraction?)

Answer 7

due to the sunlight

Answer 8

ozone layer