Why is the sky blue, and not for example green or red?
145839
Blue is a short wavelength, shorter than green or red, and our eyes are sensitive to it. The reason the short wavelengths are scattered out of sunlight is because of the size of the nitrogen and oxygen molecules in the air; they are much smaller than the wavelength of light, so they scatter the shortest wavelengths, which are towards the blue end of the spectrum. \n\nOf course, the sky is sometimes green, during a green flash or red, at sunrise or sunset when the red of the sun is reflected from dust and air droplets in the air. \n\nAt sunset, the sunlight has to travel through more air, so more blue gets scattered out, leaving orange, and eventually red light, as more blue gets removed. \n\n(sorta white sunlight)-(blue light gets scattered out)=(yellow sunlight)\n\nAnd as the sun sets:\n\n(sorta white sunlight)-(even more blue light removed)=(orange or red sunlight)
66724
Rayleight Scattering.\n\nThe blue color of the sky is caused by the scattering of sunlight off the molecules of the atmosphere. This scattering, called Rayleigh scattering, is more effective at short wavelengths (the blue end of the visible spectrum). Therefore the light scattered down to the earth at a large angle with respect to the direction of the sun's light is predominantly in the blue end of the spectrum.
844556
Yes! Of course here in the UK it is not always 'blue' below the clouds! \n\nThe reason for the sky being blue is that 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\nTo get a fuller explanation (if you can bear it!) see the link below.\n\nGood question!\n\nx
1088788
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.\n\nGo here for a detailed explanation and a cute little picture to show you! lol\n\nhttp://math.ucr.edu/home/baez/physics/General/BlueSky/blue_sky.html
239803
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\nLink below explains more and has a diagram:
28618
The sky is blue because the nitrogen in the air scatters the blue light out of sunlight. \n\nOur sun is a yellow star, so it has slightly yellow light, but it is still pretty close to white light.\n\nSunlight on earth is slightly yellower than it is in space because some of the blue light in sunlight gets scattered out by the presence of nitrogen in the air, making the sky appear blue. So \n\n(White light) - (Some Blue light) = (Yellow light)\n\nAs the sun sets, the sunlight travels through more air, and the nitrogen scatters out more blue light and the sun appears first orange, and then finally red.\n\nAs the sun starts to set:\n\n(White light) - (More Blue light) = (Orange light)\n\nand finally as the sun has almost set:\n\n(White light) - (Lots of Blue light) = (Red light)
336150
Why is the sky blue ?  Why is the sun yellow ? That is a very logical question guy please, lemme see um cause maybe JUST MAYBE if we do it standing up like you guys, how do I put this umm not a pretty picture right ?  so duh !
680108
There are two reasons. Both are caused by a property of light -- it is made up of different wavelengths.\n\n(1) When light passes through our atmosphere, it diffracts & blue wavelength gets scattered towards earth. This is why the sky is blue. When viewed from the beach, the sea is also blue because it reflects the sky, of course.\n\n(2) Another reason is not by diffraction, rather, light under the sea is blue because water absorbs longer wavelength of light through distances over about 20 metres.
1050973
the blue color of a beautiful sky
375813
Sky is blue because air is not perfectly transparent.  If you look through many miles of it, it gives a bluish color. [This is another way of saying that blue light is scattered by the atmosphere.] The only direction in which you can look through enough miles of air is upwards.  \n\nClouds are not always white.  Clouds can also turn grey or black and they are made out of the very same water molecules they were before.  It all has to do with how large the particles are, when the cloud is newly formed all the water droplets are very tiny and therefore all light is reflected, ie they look white.  As the tiny droplets glom together into larger pieces of airborne water, light can be absorbed more and more, and the cloud turns darker.
563373
it all depends....\n\nthe color of the sky depends on the weather...ranging from light blue to dark gray...or black at night\n\nthe color of the grass depends on how dry it is...usually it's varying shades of green but if it's really dry...then baige or brown-ish\n\nthe sun is yellow
178836
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\nAs 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.
87869
The sky is technically clear - this can be seen on any clear night. 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.
388504
because of tyndall effect as the blue clour as a longer wave length in the spectrum of colours it gets scaterd more in the sky \n\n\nmxwltan\n6 minutes ago\n\n\n\nThe 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
989881
The main reason light from the sky is blue is Rayleigh scattering (named after Lord Rayleigh), which is the scattering of light, or other electromagnetic radiation, by particles much smaller than the wavelength of the light. It occurs when light travels in transparent solids and liquids, but is most prominently seen in gases.
59243
The light during the day comes from our star, the sun. The sunlight has to travel through air to get to us. The sunlight looks white, but it has many colors in it (for example, a prism or a rainbow breaks the sunlight into its colors so we can see them). \n\nSome of the blue part of the sunlight cannot go through the air without getting bounced around first by the air, and so it makes it look like the blue is coming from the air in the sky instead of the sun. That is why the sky looks blue.
378185
Particles in the air refract the white light of the sun into the spectrum.  The sky is blue because blue gets through the easiest.