Why is the sky blue where there are no clouds?

Question

Why is it not black or green or purple?

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.

Answer 2

It doesn't depend the clouds. 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.

Answer 3

The colour of the sky is a result of diffuse sky radiation and the fact that air is actually a very transparent blue color. On a sunny day the Earth sky usually looks as a blue gradient — dark in the zenith, light near the horizon (due to Rayleigh scattering). It turns orange and red during sunrise and sunset, and becomes black at night.

Sky luminance distribution models have been recommended by CIE (the International Lighting Commission) for the design of daylighting schemes. Recent developments relate to “all sky models” for modelling sky luminance under weather conditions ranging from clear sky to overcast sky.........

Answer 4

The particles in the upper atmosphere refract the blue end of the spectrum from the sun, this then appears blue. When its cloudy, you cannot see the upper atmosphere. The sun is actually white (emitting all visible wavelengths), but when the blue has been remove ed from white light, it will appear yellow.

Also related to previous questions as to why the red sky at night predicts good weather - all related to diffraction of light by the atmosphere.

Answer 5

White light from the sun is composed of the colors in the VIBGYOR [Violet, Indigo, Blue, Green, Yellow, Orange, Red] band and atmospheric moisture scatter blue the most in this band.

Answer 6

i will attempt to place it in simple terms. solar includes all colorations of the rainbow. Blue waves (indigo and violet too) have the shortest wave length and subsequently return and forth swifter than the different colorations. The atoms interior the ambience are hit by skill of blue waves first and address that color. different easy waves return and forth contained in direction of the ambience without being absorbed and contemplated. At sunset, you notice greater of those colorations simply by fact the solar's easy could desire to return and forth by greater ecosystem simply by perspective of the solar in terms of you relative place in the international. ecosystem further west the place the solar is greater interior the sky displays greater of the blue waves first, so the skies further east the place the solar is putting mirror greater of the longer wavelength colorations, like pink and orange. optimistically this makes some sense. Clouds are white simply by fact water displays all colorations which seem white whilst blended. of direction all of it extremely relies off of my memory from college, the place I did significant in earth technological know-how, yet those days are fairly hazy. I regards to previous posts. The oceans seem blue simply by fact they mirror the sky, no longer any opposite direction around. all of us who has had a pitcher of water is unquestionably-known with that water is obvious.

Answer 7

That is the color of the paint that was delivered the day the fairies painted the sky.

No really, blue is God's favorite color.

Come on work with me. It's the color of the worlds celing.

Ya gotta follow me on this. The aliens wanted to keep us guessing.

Did you get it yet.

The freaking sky is blue because it is.

Some people never learn.

Answer 8

Our atmosphere only allows light of certain wavelengths through. Blue happens to be of just the right frequency to pass through the atmosphere.

If you type your question into any search engine, a multitude of sites will come up that will have diagrams and what not to help you understand.

Answer 9

Water droplets suspended in the air reflect blue wavelengths of light, so that the other wavelengths proceed through, while blue light is scattered in the atmosphere, yielding the blue color, just as many oceans or lakes appear blue.

It's the water in the air that does it.

Answer 10

Because the way the sunlight looks through the atmosphere it filters out all the other colors.