why is the sunset red?
414202
(m)\n\nAs the sun begins to set, the light must travel farther through the atmosphere before it gets to you. More of the light is reflected and scattered. As less reaches you directly, the sun appears less bright. The color of the sun itself appears to change, first to orange and then to red. This is because even more of the short wavelength blues and greens are now scattered. Only the longer wavelengths are left in the direct beam that reaches your eyes\n\nThe sky around the setting sun may take on many colors. The most spectacular shows occur when the air contains many small particles of dust or water. These particles reflect light in all directions. Then, as some of the light heads towards you, different amounts of the shorter wavelength colors are scattered out. You see the longer wavelengths, and the sky appears red, pink or orange
160404
Because the sun is going down or coming up
661394
it occurs when solar radiation from the sun interacts with the magnetic field around the Earth (its strongest around the poles..so thats why theres a northern..AND southern lights...and no "Middle" lights lol)\n\ni can't wait to see it some day
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."
1122701
The coloration you are seeing in the sky at sunset is due to the sunlight being reflected and refracted by particles in the atmosphere.  If clouds are present, since they are mostly made up of tiny water droplets, help to refract the sunlight into a series of colorful hues.  Interestingly enough, pollution and dust have the same effect which is why desert sunsets always seem more majestic, even when there are no clouds in the sky.
575845
It is due to refraction, not diffraction.  Red is not bent the most in a prism, violet is bent the most.  \n\nWhen the sun is on the horizon, its light has to travel through many miles of atmosphere before it gets to our eye.  Since the blue end of the spectrum is bent the most through refraction, it is completely scattered away by the time the light gets to us.  Therefore, the only colors left are the red and orange.\n\nThis is the same reason the sky is blue (no it is not blue because of the reflection of the oceans!)  The blue end of the spectrum is scattered the most, thus illuminating the sky more than the other colors.  Actually, since violet is bent more than blue, the sky is actually more a violet color, but our eyes are more sensitive to blue, so we see a blue sky.
918082
because the sun has gone over the horizon
186237
It depends on what planets you are talking about...  Mars appears red primarily because of the makeup of the planet's surface itself...   The outer planets like Neptune appear to have the colour they do because of the atmospheric makeup (gases surrounding it)
66169
The sun's rays hit the Earth's atmosphere, where the light is scattered by nitrogen and oxygen molecules in the air. The blue wavelength of this light is affected more than the red and green wavelengths, causing the surrounding air to appear blue. At sunset, the sun's light passes farther through the atmosphere, deflecting and decreasing the blue in the air. Scattering by dust particles and pollution in the air causes the sunset to appear red.
134964
Red because it's a brighter color (traffic lights and cars' brake lights are red)
590904
It isn't really. Check out a sunset. Check out satellite imagery. Check out my new toupee.
995583
The red color is found in many soils around the world.\nThe cause of that is the presence of oxides and hydroxides of Fe and Al.\nThose soils are known as ''weatherized'', usually done by many, many years of exposure to heat and humidity.
87204
Do you mean the green flash?\nIt is there because diffraction of sunlight in the atmosphere.\nAt sunset the thickth of the air layer through whick the sunray travels, is in a maximum.
100945
If you want a very simple answer, here it is:\n\nThe white light from the sun is a mixture of all colours of the rainbow.\n\nA 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.
17883
Sunlight is made up of all the colors of the rainbow: red, orange, yellow, green, blue, and violet. The gas molecules in the atmosphere interact with the sunlight before the light reaches our eyes.\n\nThe gas molecules in the atmosphere scatter the higher-energy (high frequency) blue portion of the sunlight more than they scatter the lower-energy red portion of the sunlight (this is called Rayleigh scattering, named for the physicist Lord John Rayleigh). The Sun appears reddish-yellow and the sky surrounding the Sun is colored by the scattered blue waves.\n\nWhen the Sun is lower in the horizon (near sunrise or sunset), the sunlight must travel through a greater thickness of atmosphere than it does when it is overhead, and even more light is scattered (not just blue, but also green, yellow, and orange) before the light reaches your eyes. This makes the sun look much redder. \n\nA musch better and detailed explaination is availabe at the following websites :\n\nhttp://www.sky-watch.com/articles/skyblue.html\nhttp://world.std.com/~mmcirvin/bluesky.html\nhttp://webexhibits.org/causesofcolor/14.html
12251
The scientific answer is very long which involves dipole scattering, charged particles vector potential and much more.  There is a simple answer though.  Think of how prism works.  When a light hits the prism, what happens?  The answer is the prism breaks the white light into visible color, red, orange, yellow, green, blue, and violet (these are the rainbow color).  Our atmosphere is filled with dust particles.  So when sun ray hits the particles in the atmosphere, it breaks the white light like the prism.  The color blue has the strongest wavelength out the rainbow colors.  Therefore, it effects more than the red and green wavelength, causing the surrounding air to appear blue.  But during the sunset, the sun light passes farther through the atmosphere causing them to deflect and decrease the blue color. So sunset appear to be red.
124314
Actually, this happens only under certain atmospheric conditions, when the air is quite clear. It is because the speed of light in the layers of air near the ground is slower than the speed of light in layers of air above that. Therefore, just like a lens, the light is bent by this gradient in the speed of light. \n\nRefraction of light is a wavelength-dependent phenomenon. The longest wavelengths are bent, or refracted the least. and the shortest wavelengths are bent the most. The reds, yellows and oranges are the long wavelengths, and they will bend the least, and will head off into space. The shorter wavelengths, the blues and greens and violets will be bent down by the atmosphere to be visible at the ground. In fact, the sun is actually below the horizon for the last few minutes of the sunset. The light has to bend around the earth, and the color that gets bent the most includes the short wavelengths. \n\nWhy do we see green in the green flash, and not violet or blue? There is also Rayleigh-Tyndall scattering going on, caused by the small nitrogen and oxygen molecules in the air. The shortest wavelengths are most scattered by the air molecules, and are scattered out of the sunlight, leaving longer wavelengths for us to see. The blues and violets have very short wavelengths, and are therefore scattered the most. (This is the same process that creates blue skies and orange and red suns at sunset). However, in this case, the yellows and reds and oranges are not present in the sunlight as the sun sets below the horizon, but have travelled out into space, so only the greens, blues and violets remain. The blues and violets are scattered away, leaving the green for us to see as a green flash. \n\nA more complete explanation complete with pictures is in the references.\n\nIt is also interesting to note that the moon can also exhibit a green flash, or a green edge (and also a red edge, in a kind of red flash). At the poles, when the sun is barely below the horizon for hours, the green flash can last for hours apparently, according to friends that have seen it.