Why is the sky blue and not black ?
538914
ATMOSPHERE,LIGHT WAVES see my source for details.
1113645
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.\n\n\nBecause the universe is not infinitely old, that puts a limit to how long the\nlight from all those stars can have travelled. So some of the light has not\ngotten here yet. Because stars do die out, that means that their light dies\nout too - which means that we may get the light from some stars at one time,\nand the light from some other stars at a different time, but not all the \nlight\nof all the stars that everywhere put together. Finally, because the \nuniverse is\nexpanding, the light gets weaker before it gets to us. All in all, this means\nthat there is not enough light from all those stars to make any point in \nspace\nbright.
40975
next to why is the sky blue, this has gotta be the second most frequently-asked question.  congratulations on making such an innovative and creative joke!\n\nthis page should help you out:\nhttp://www.style.org/unladenswallow/
539871
in the summer the sky is blue because the atmosphere dullens the color of outer space but in the winter the sky is the color it is because of the water particles that are in the sky
117362
One meaning to this is that you did not check the archive of previously asked questions before you posted your question about the sky's color. This has been asked and answered almost 400 times so far here (see link below). \n\nHowever, the reason the sky appears blue (at least most of the daylight hours) is that the atmosphere is mostly oxygen and nitrogen, which are just the right size molecules to scatter the blue light, but let the other colors pass unimpeded. \n\nSo when you take the blue away from the mostly white sunlight, you get sorta yellow sunlight. \n\nAs the sun sets, the sunlight passes through more air, and more blue is scattered away, leaving the sunlight even less blue, that is, more orange. \n\nAs the sun sets even farther, even more blue is scattered away, and the sunlight appears red.
176242
I have no idea what you are asking. The question "why is the sky blue?" has been asked over 500 times here. Use the search engine to find some great material. \n\nYou want data that proves the sky is blue? The variable might be the wavelength of the light (or frequency). If you want to learn about the equations, look up Rayleigh-Tyndall scattering. The scattering intensity is roughly proportional to L^(-4), where L is the wavelength.
24151
Everyone else is wrong. This has nothing to do with water. The sky is blue because as the light waves pass trhough the air they collide with molecules, effectively scattering the blue wavelenghts of light. This is demonstated by the fact that the sky at lower angles appears more blue, because there is more air that the light must travel through.
31576
The Earth's sky is blue because the air molecules (largely nitrogen\nand oxygen) are much smaller than the wavelength of light. When light\nencounters particles much smaller than its wavelength, the scattered\nintensity is inversely proportional to the 4'th power of the\nwavelength. This is called "Rayleigh scattering," and it means that\nhalf the wavelength is scattered with 2**4 = 16 times more intensity.\nThat's why the sky appears blue: the blue light is scattered some 16\ntimes more strongly than the red light. Rayleigh scattering is also\nthe reason why the setting Sun appears red: the blue light has been\nscattered away from the direct sunlight.\n\nThus, if the atmosphere of another planet is composed of a transparent\ngas or gases whose molecules are much smaller than the wavelength of\nlight, we would, in general, also expect the sky on that planet to\nhave a blue color.\n\nIf you want another color of the sky, you need bigger particles in the\nair. You need something bigger than molecules in the air---dust.\n\nDust particles can be many times larger than air molecules but still\nsmall enough to not fall out to the ground. If the dust particles are\nmuch larger than the wavelength of light, the scattered light will be\nneutral in color (i.e., white or gray)---this also happens in clouds\nhere on Earth, which consist of water droplets. If the dust particles\nare of approximately the same size as the wavelength of light, the\nsituation gets complex, and all sorts of interesting scattering\nphenomena may happen. This happens here on Earth from time to time,\nparticularly in desert areas, where the sky may appear white, brown,\nor some other color. Dust is also responsible for the pinkish sky on\nMars, as seen in the photographs returned from the Viking landers.\n\nIf the atmosphere contains lots of dust, the direct light from the Sun\nor Moon may occasionally get some quite unusual color. Sometimes,\ngreen and blue moons have been reported. These phenomena are quite\nrare though---they happen only "once in a blue moon...." :) The dust\nresponsible for these unusual color phenomena is most often volcanic\nin origin. When El Chicon erupted in 1982, this caused unusually\nstrongly colored sunsets in equatorial areas for more than one year.\nThe much bigger volcanic explosion at Krakatoa, some 110 years ago,\ncaused green and blue moons worldwide for a few years.\n\nOne possible exception to the above discussion is if the clouds on the\nplanet are composed of a strongly colored chemical. This might occur\non Jupiter, where the clouds are thought to contain sulfur, phosphorus,\nand/or various organic chemicals.\n\nIt's also worth pointing out that the light of the planet's primary is\nquite insignificant. Our eyes are highly adaptable to the dominating\nillumination and perceive it as "white," within a quite wide range of\npossible colors. During daytime, we perceive the light from the Sun\n(6000 K) as white, and at night we perceive the light from our\nincandescent lamps (2800 K, like a late, cool M star) as white. Only\nif we put these two lights side-by-side, at comparable intensities,\nwill we perceive a clear color difference.\n\nIf the Sun was a hot star (say of spectral type B), it's likely we\nstill would perceive its light as "white" and the sky's color as blue
1036658
When sunlight travels through the atmosphere, blue light scatters more than the other colors, leaving a dominant yellow-orange hue to the transmitted light. The scattered light makes the sky blue; the transmitted light makes the sunset reddish orange. \nI could go into explaining it, but I'm too tired at the moment. Check out here:
1089706
When transmitted light such as sunlight enters our atmosphere it collides with the oxygen and nitrogen atoms. The color with the shorter wavelength is scattered more by this collision. Because violet and blue are the shortest wavelengths the sky appears to be violet / blue. But because our eyes are more sensitive to blue light than they are violet light, we perceive the sky as blue.\n\nIt is because blue light from the sun strikes the air molecules and scatters and our eyes perceive it as blue.\n\nBlue in sunlight collides with air molecules and our eyes see it as blue.
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Sky blue\n--------\n\nYou did not check the archive of previously asked questions before you posted your question about the sky's color. This has been asked and answered more than 400 times so far here. \n\nHowever, the reason the sky appears blue (at least most of the daylight hours) is that the atmosphere is mostly oxygen and nitrogen, which are just the right size molecules to scatter the blue light, but let the other colors pass unimpeded. \n\nSo when you take the blue away from the mostly white sunlight, you get sorta yellow sunlight. \n\nAs the sun sets, the sunlight passes through more air, and more blue is scattered away, leaving the sunlight even less blue, that is, more orange. \n\nAs the sun sets even farther, even more blue is scattered away, and the sunlight appears red.\n\nGrass Green\n-------------\n\nFrom the color of chlorophyll, the chemical that plants use to capture energy from sunlight. \n\nEarth Boring\n-------------\n\nIf the earth is boring, then what is not boring to you?
354871
Because it's blue. . .\n\nWhen sunlight travels through the atmosphere, blue light scatters more than the other colors, this makes sunlight and visable sun rays a yellow-orange color. The scattered light makes the sky blue; the transmitted light makes the sunset reddish orange.\n\nBecause this scattered light is so brightly blue we cannot see through the atmposhere into space. . .only at night when there very minimal light to refract seeing as how the sun had set is on the other side of the planet!
159646
The blueness of the sky is caused by sunlight scattering off particles in the atmosphere.  The intesity of the scattering is a strong function of the wavelength of light, so the blue light (one end of the spectrum) is observed more than red (the other end).
191878
The sky is blue because of the ozone layer, which is blue. The ozone layer is blue because (have you ever tried to shine light through a triangular pyramind (glass)?) It filters everything but blue color...why? I don't know. Uh...I'm not sure, probably because they want to know more about female sex organs because girls have 2 and we have 1 ugly sex organ that's not exactly as attractive as girls. Not that I'm a pervert...only nerds are.
1048733
The sky is blue partly because air scatters short-wavelength light in preference to longer wavelengths. \nWhere the sunlight is nearly tangent to the Earth's surface, 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, at sunrise and sunset.\n\nso\n\nAn old weather predicting adage rhythmically states: \n\nRed sky at night, Sailors' delight.\nRed sky in morning, Sailors take warning. \n\nHumidity in the air is indicated by red skies at sunset-- red sky at night-- or, at sunrise-- red sky in morning. The forming raindrops scatter the short-wavelength blue light so that only the long-wavelength red light reaches the observer.
494735
"The sky is blue partly because air scatters short-wavelength light in preference to longer wavelengths. Where the sunlight is nearly tangent to the Earth's surface, 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, at sunrise and sunset."
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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...\n\nHowever, 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. \n\nThe atmosphere is the mixture of gas molecules and other materials surrounding the earth. It is made mostly of the gases nitrogen and oxygen. Argon gas and water (in the form of vapor, droplets and ice crystals) are the next most common things. There are also small amounts of other gases, plus many small solid particles, like dust, soot and ashes, pollen, and salt from the oceans.