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.
In Mars the sky is a reddish/orance colour due to the small particles of Martian dust in the atmosphere. Mercury has no atmosphere so the sky is black as space reaches the surface (as it does on the moon).
2007-07-12 16:35:49
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answer #1
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answered by Anonymous
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Technically, the Moon has no 'sky'. If you stood on the Moon and looked up, you would be looking into deep space.
The Earth's sky is blue because blue light scatters heavily in air, while red light barely scatters at all. The degree to which light scatters in air is proportional to the frequency of the light, to the fourth power, so blue light scatters far more than red.
The net effect of this is that the blue light coming from the Sun (in a straight line) ends up getting deflected all over the place. So, we see blue light hitting our eyes from every direction at once. The red light coming from the Sun barely scatters at all, though, so we see red light hitting our eyes only from the direction of the Sun. Therefore, we see the Sun as possessing all colors (making it a yellowish-white), while the rest of the sky is blue.
Any planet with an atmosphere similar to Earth's would have the same kind of blue sky. However, the atmosphere of Venus is not like Earth's. Venus's sky appears yellow-brown in color. This is not due to scattering, but rather is due to the presence of chemicals (such as sulfur compounds) in Venus's clouds that absorb blue light.
2007-07-12 23:28:33
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answer #2
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answered by lithiumdeuteride 7
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We owe some of our most spectacular atmospheric phenomena to various types of scattering: the blue of the sky, the red of the sunset, the white of clouds and, that epitome of rare occurrences, the blue moon. Most blue and green bird-feather colors involve scattering, as do many animal and some vegetable blues.
Our sky is colored because our atmosphere makes blue light when sunlight passes through it. This phenomenon is called "scattering." It is similar to when sunbeams reveal themselves in the presence of dust, most spectacularly in cathedrals. The atmosphere causes the sky to be colored.
If there were no atmosphere, the sky would appear black, like the lunar sky in Apollo pictures taken from the moon. But even a black sky has some lightness... Even at night, the sky always has a faint color, called "skyglow" by astronomers. Atmospheres also cause skyglow from faint airglow in the upper atmosphere (a permanent, low-grade aurora), and starlight scattered in the atmosphere. Even if there were no atmosphere, faint skyglow is caused by sunlight reflected off interplanetary dust (zodiacal light), and background light from faint, unresolved stars and nebulosity.
2007-07-13 00:06:13
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answer #3
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answered by Soccermaster 4
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The color of the sky doesn't really have anything to do with the oceans.
The sky is blue because the molecules that predominantly make up our atmosphere--nitrogen and oxygen--refract light in the blue part of the visible light spectrum.
Blue light from the Sun is absorbed and scattered by air molecules. If the air wasn't there, the Sun would look bluer than it does with the air there.
Visible light has three primary colors: red, blue, and green. (Note: this is different from the 3 primary colors artists teach: red, blue, and yellow, probably because of chemistry more than electromagnetism, a.k.a. light) When these types of light are mixed together, they produce white light. With most of the blue light from the Sun scattered, the remaining red and green look yellow together.
2007-07-12 23:33:36
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answer #4
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answered by Logan 5
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Light coming from the sun is what's called "white light" White light contains all the colors of the rainbow. When it enters Earth's atmosphere this light is separated into its individual colors by chemical elements in the atmosphere and scattered across the sky. Nitrogen is the most abundant element in our atmosphere, and that element scatters the color blue across our sky more than the other colors. In space, there is no atmosphere to separate colors from the white light and space looks black.
2007-07-12 23:30:29
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answer #5
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answered by Chug-a-Lug 7
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Everyone likes to label it as Rayleigh Scattering but still very few explain that term. The Sun emits pure white light. As the sun comes up or sets, the light has more air molecules to travel thru, giving a longer bend to the white light, the reds having a longer frequency, and due to the longer bend of the light from the amount of air, we see reds at sunrise and sunset. AS the Sun climbs higher, it goes thru less air to get to ours eyes. Hence the light is not refracted as much, less bend you might say, blues have a shorter wavelength, so we see blue. Notice on clear cloudless days, the sky is real blue in the middle around noon and appears whitish at the horizon. We are looking at light traveling away from us at the horizon so we see the white light as from the sun. On cloudy or foggy days, less blue because the white light is being filtered by the greyness of the clouds or fog.
2007-07-13 01:25:35
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answer #6
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answered by orion_1812@yahoo.com 6
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I think it has something to do with the composition of the atmosphere, and the fact that nitrogen is most abundant. If you pass energy through it (like the sun's energy) every element produces a unique spectrum. A good example is fluorescent lights, they have some element in them (tungsten, I think. don't quote me on that) that, when you run electricity through it, produces all the colors (white light). Since we have mostly nitrogen in the atmosphere, and it's particular spectrum is mostly blue, the sky appears blue.
I COULD be 100% wrong on this, but I remember something along these lines from Chem class. I need someone smarter to back me up here.
2007-07-12 23:24:39
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answer #7
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answered by jesse s 3
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the sky is black on the moon because there's no atmosphere on the moon!!! therefore NO SKY ON THE MOON! duh
the sky is blue because it's the suns rays reflecting off of the atmosphere and primarily earths oceans.
2007-07-12 23:22:41
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answer #8
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answered by threeonspeed 4
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Earth's sky reflects the water in the ocean, which is blue.
2007-07-12 23:52:48
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answer #9
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answered by S 7
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it is blue because it is the color of our oceans reflecting off of earths atmosphere and back to us, its not actually blue but it appears that way during the day, at night when the sun is not there to make the reflection then the sky is clear and therefore allows us to see outer space (assuming you dont live in a city)
2007-07-12 23:22:52
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answer #10
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answered by camo4213 3
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