Jeremy_R
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« on: June 27, 2011, 09:55:42 AM » |
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Without light, outer space in nothing, no color, nothing. The sun is red hot, amd gives off white light, and if any color, why blue? In the evening it makes sense if its pink or orange, but why blue?
Additional question: How do storms make the sky redder/greenish?
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Tiffany
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« Reply #1 on: June 27, 2011, 05:52:50 PM » |
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I'm pretty sure the sun reflects off the ocean thus causing it to turn the sly blue  |
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A
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« Reply #2 on: June 28, 2011, 12:13:41 AM » |
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We see our sky through our atmosphere which filters out certain light waves. Kind of how water looks blue when you know it's clear... it's all about the light waves and what parts of the spectrum get through and what ones don't .
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Petrusclavus
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« Reply #3 on: June 28, 2011, 01:15:08 AM » |
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Sunlight hits the atmosphere, some of it scatters as it meets dust, water, gas molecules.
The photons are re-emitted but with moderate scattering we see light coming from the entire sky/atmosphere. Most of the light actually comes direct to you from the sun - but you filter that out as you cannot look directly at the sun.
With absorption/re-emission some energy is lost - more is lost in the red end of the spectrum than in the blue end.
Now the scattered light is more blue - ergo we see the sky as blue.
It's called Rayleigh Scattering.
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Terry_Scott
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« Reply #4 on: June 28, 2011, 02:02:53 AM » |
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The sky is blue because the atmosphere scatters photons of higher energy more than photons of lower energy. Scattering means that a photon is absorbed and then reemitted by the molecules that make up the air. So the violet light is scattered the most while even more energetic ultraviolet photons are absorbed all together. Blue and green comes next. The sun puts out more blue photons than violet so the sky isn´t violet. And blue light is scattered more then green light so the sky isn´t green. Instead the dominant color of the sky is blue.
At sunrize and sunset the photons have to travel through more atmosphere so they are scattered even more. Even red and yellow photons are scattered making the sun and the sky look much redder.
The reason the sun looks yellow to some (it looks white to others) is because of our eyes relatively poor ability to percieve color. The sun actually emitts most light in between the blue and green parts of the spectrum. Our eyes however only have the ability (through our light sensitive cones) to see red, yellow and blue. The light cones in our eyes suck at picking up blue-green photons. Our brains then composes colors from the limited information our eyes send it and that information says yellow because our eyes sees violet light the worst (it is also scattered by the air). Red is the color we see the least after violet so red is out. It isn´t the dominant frequency anyway. We don´t see blue and orange very well either. Green and yellow is best but since green is heavily scattered the sun seems yellow (to most).
Sky is blue due to scattering by Raman EFFECT
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nawstman
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« Reply #5 on: June 28, 2011, 04:46:05 AM » |
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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.
The white light from the sun is a mixture of all colours of the rainbow. This was demonstrated by Isaac Newton, who used a prism to separate the different colours and so form a spectrum. The colours of light are distinguished by their different wavelengths. The visible part of the spectrum ranges from red light with a wavelength of about 720 nm, to violet with a wavelength of about 380 nm, with orange, yellow, green, blue and indigo between. The three different types of colour receptors in the retina of the human eye respond most strongly to red, green and blue wavelengths, giving us our colour vision.
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O_Respondedor
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« Reply #6 on: June 28, 2011, 04:57:55 AM » |
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The color you see in the sky is the color of the gases in the atmosphere in large quantities when struck by light from the Sun.
If you take a prism, will see that the sunlight that passes through the prism is separated into seven colors (red, orange, yellow, green, blue, indigo and violet). In the late afternoon, the atmosphere the sunlight passes through a large amount of gas, which prevents 6 colors pass through the atmosphere, and only the red light can pass through more atmosphere.
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oklatonola
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« Reply #7 on: June 28, 2011, 05:09:35 AM » |
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The sky is blue because the wavelengths of blue light and the diameters of air molecules, N2, O2, CO2, and atoms, Ar, are approximately equal. Blue light waves slam into an air molecule and are reflected off. Shorter wavelengths are preferentially scattered out of the atmosphere. That's what creates the purple/violet layer of the atmosphere above the blue layer of atmosphere of images of a limb of the Earth taken through a Space Shuttle or an ISS window show. At sunrise, moonrise, sunset, and moonset. longer wavelengths of visible light (red, orange, yellow, pink) are both preferentially scattered and refracted by the atmosphere to the surface of the Earth. Water molecules have larger diameters, so they scatter all the wavelengths of visible light. That's why water vapor clouds are white to gray to almost black. It's called Rayleigh scattering and Mie scattering. http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.htmlRed skies and storms: http://en.wikipedia.org/wiki/Red_sky_at_morningLots of wind can create dust stroms and can launch red dust pretty high into the atmosphere. I've been through several dust storms in central OK. All that red dust pelting into my face came from Texas, of course. lol!!! Dust in the atmosphere can also refract sunlight to give the sky that tornadic green color. |
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Orfeo
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« Reply #8 on: June 28, 2011, 05:26:46 AM » |
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Sunlight interacting with the Earth's atmosphere makes the sky blue. In outer space the astronauts see blackness because outer space has no atmosphere.
Sunlight consists of light waves of varying wavelengths, each of which is seen as a different color. The minute particles of matter and molecules of air in the atmosphere intercept and scatter the white light of the sun. A larger portion of the blue color in white light is scattered, more so than any other color because the blue wavelengths are the shortest.
When the size of atmospheric particles are smaller than the wavelengths of the colors, selective scattering occurs-the particles only scatter one color and the atmosphere will appear to be that color. Blue wavelengths especially are affected, bouncing off the air particles to become visible.
This is why the sun looks yellow from Earth (yellow equals white minus blue). In space, the sun appears white because there is nothing in between to scatter its white light.
At sunset, the sky changes color because as the sun drops to the horizon, sunlight has more atmosphere to pass through and loses more of its blue wavelengths. The orange and red, having the longer wavelengths and making up more of sunlight at this distance, are most likely to be scattered by the air particles.
The scattering of visible light by atmospheric gases is most correctly called the Tyndall effect, but it is more commonly known to physicists as Rayleigh scattering after Lord Rayleigh, who studied it in more detail a few years later.
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