what makes the sky turn red at sunset?
367501
"The red hues of the sky at sunset and sunrise are caused by the Rayleigh scattering, of blue light, by statistical fluctuations in the density of Earth's atmosphere."\nhttp://en.wikipedia.org/wiki/Sunset\n\n... which is...\n\n"Rayleigh scattering (named after Lord Rayleigh) is the scattering of light, or other electromagnetic radiation, by particles much smaller than the wavelength of the light."\nhttp://en.wikipedia.org/wiki/Rayleigh_scattering\n\nCheers!
880277
It has to do with the light it recieves from the nearby stars but it also depends on what the gas cloud is made of.  Hydrogen emits (and blocks) red light.  Other forms of light are also reradiated as red.  As the temperature of the gas cloud increases (due to recieving radiation) infrared emissions would increase also.
411513
Dust in the upper atmosphere of Earth can make the moon appear to be yellow or orange, even red. The effect is strongest when the moon is near the horizon.
908551
The aurora borealis is an atmospheric phenomenon. \n\nThe sun's Solar wind contains a lot of electrons and other charged particules which then hit atoms in the upper atmosphere. The collision energises the atoms and causes electrons in the atoms to shift energy levels, and release energy as light. \n\nThe colours you see are due primarily to solar wind particles energising oxygen and nitrogen atoms.
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.
308063
Red sky at night, sailors' delight.  Red sky in morning, sailors take warning.  Applies in tropical latitudes.
17956
The most likely way is to have some sort of atmospheric distortion.  For example followin a volcanic eruption in Mexico, the sun appeared to be green due to the amount of dust and ash that was put up into the air.
377468
The moon is red some days because of the filtering of sunlight from earth's atmosphere.
344653
First off why is the sky any color at all and not black?\nThe answer -- the presence of the atmosphere -- oxygen molecules absorb energy and release at pretty much a random angle(Rayleigh scattering). So the light from the sun is "diffused" around the atmosphere and when it reaches our eyes it come in from all directions -- creating the colored sky effect.\n\nNow on to the 2nd question why is the sky specifically blue. Blue is high energy color(it is created by high frequency waves) so it does not spread as much as other colors. In fact the sky is not uniform blue -- Come out of your house on a clear sunny day and you will see that the sky is the bluest directly above your head but it gets more and more white as you look toward horizon. This means that blue light diffuses the least creating blue appearance around the sun -- but as you look further from the sun more colors are visible creating the white effect. \nThe Sky may also be seen in weird colors like red and orange when the sun is at the sharp angle with the atmosphere(dusk and dawn).
1055537
Here is something interesting to think about: When you look at the sky at night, it is black, with the stars and the moon forming points of light on that black background. So why is it that, during the day, the sky does not remain black with the sun acting as another point of light? Why does the daytime sky turn a bright blue and the stars disappear? \n\nThe first thing to recognize is that the sun is an extremely bright source of light -- much brighter than the moon. The second thing to recognize is that the atoms of nitrogen and oxygen in the atmosphere have an effect on the sunlight that passes through them. \n\nThere is a physical phenomenon called Rayleigh scattering that causes light to scatter when it passes through particles that have a diameter one-tenth that of the wavelength (color) of the light. Sunlight is made up of all different colors of light, but because of the elements in the atmosphere the color blue is scattered much more efficiently than the other colors. \n\nSo when you look at the sky on a clear day, you can see the sun as a bright disk. The blueness you see everywhere else is all of the atoms in the atmosphere scattering blue light toward you. (Because red light, yellow light, green light and the other colors aren't scattered nearly as well, you see the sky as blue.)
404054
Yes. Anywhere that there is lightning there is a possibillity for red lighting. Red lightning is caused by, lighting traveling from cloud to cloud. The clouds then distort the color.
86687
Nothing. A slight change in temperature if that. Kind of like a cloud going over the sun. All it is after all is a shadow passing across the sun.
1025313
I was interested by this so I did a bit of research.\n\nApparently:\n\n"When the air is clear the sunset will appear yellow, because the light from the sun has passed a long distance through air and some of the blue light has been scattered away.  If the air is polluted with small particles, natural or otherwise, the sunset will be more red."\n\nSo, I suppose the answer would be a more 'orange' sunset, and possibly less vibrant.  Wikipedia says: the "Color of a sunset may be enhanced by atmospheric phenomena such as clouds, smoke and smog."
581391
as the earth spins on it's axis the distance from any one given point on earth to the sun changes throughout the day. Near midday the sun is directly above you and closest to you, thus it is very bright. As the day goes your point on earth spins away from the sun, making it further away, and you are also seeing it through all the dust in the atmosphere, making it less bringht and appear yellow/red.
31265
Frosty is right, Otisabi is wrong. The round shape of the atmosphere bends the light. You also get a reddish taint to the moons colour when it's close to the horizon. This is due to the red part of the light reflected from the moon hitting your eye, while the rest is into space. If you've ever looked into a round fishbowl you'll see how it distorts light to make things look larger.
105603
WHY IS THE SUNSET RED?\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.
580957
When the light from the sun hits the earth some of the light (The higher frequency or blue light) gets trapped or rather scattered by the smaller molecules in the atmosphere.  This scattering makes the sky blue because these particles reflect this blue light.\nAt night the light we are seeing is  the light of  the sun reflected off of the moon and it is much less intense.