why is the sky blue ?
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."
522607
no the sky is no actually blue, have you noticed that at night you can see space? well thats because during the day the sun ray that come through our hemisphere are hitting against the massive amount of Ocean on our Earth, they do not reflect, but instead refract off the water molecules and transmit into the air, shooting all the way back up to our hemisphere, this gives us the sight of a blue sky.
64367
Actually there is no colore\nAnd we see it blue because of light reflex in the sky.
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
966396
AHHHH !!!!A question other than why is the sky blue.  The color of the sky is colorless, clear.  Look at the shots of earth from space (on the night side) you can see earth perfectly, no color enhancement.  Look up at the stars on a clear night, you can see them without any bluish color.\n\nThe sky is only various colors when the sun is shining thru it.
505255
The sky is air.  Air is transparent, mostly.  However, air does slightly bend very high frequencies of visible light.  These frequencies include purple and blue.  This makes the sky appear blue.\n\nWhen the Sun is near the horizon at sunrise and sunset, its light is passing through much more air (about 4000 miles' worth, instead of the overhead air that is about 50 miles thick), and much more light is bent out.  This is why the sky turns red.
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.
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.
643771
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.
369937
Why is the sky blue: Discussion \nTransmitted light (from the sun, light bulbs, fire, etc) is made up of a spectrum of colors. The longest wavelengths of light are on the red end of the spectrum and the shortest wavelengths are on the blue/violet end of the spectrum.\nWhen 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.\nOur eyes contain thousand of rods and cones, which are the receptors for light. Whenever one of the 3 Stooges pokes you in the eye you see a giant blue spot. This is because the blue receptors have been activated. Blue is one of the primary colors and thus more easily activated and seen by our eyes.
1056723
The sky is blue due to the way that light is bent, it's called Rayleigh Scattering.  Sunlight is white and white light consists of all colors but when it hits our atmosphere the light is broken up into it's component colors by the particles in the atmosphere.  The shortest wavelengths don't make it through the particles but the blue light does - hence the sky appears blue when in fact it has no color ro it (it is after all, nothing but air and water).\n\nAs others have said - grass is green because of chlorophyll - the chemical in all plants and it just happens to be green.
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.
160687
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?
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:
1121858
Light infusion from the sky gives the blue appearance that most observe
357291
the sea and sky is blue because of light refraction\n\nthe sea absorbs the longer wavelenghts of light which are near the red end of the visible spectrum, and reflects blue to our eyes which we see. \n\nthe sky reflects all of the light waves in the particles in the sky, water, CO2, Hydrogen, etc., and as it gets nearer to the earth where we can see, most of the red end of the spectrum has been absorbed and the blue is reflected back to our eyes. \n\nand sometimes there are particles that absorb other parts of the spectrum, which accounts for the colors of sunsets and etc.
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.