Uncovering the Mystery of Why the Sky Isn't Green

  • Thread starter Thread starter Ryan Lucas
  • Start date Start date
  • Tags Tags
    Green Sky
AI Thread Summary
The sky appears blue due to the scattering of white light by atmospheric particles, which preferentially diffuse blue wavelengths. During the afternoon, the sky can take on red or orange hues because sunlight travels a longer path through the atmosphere, scattering shorter wavelengths and allowing longer wavelengths to dominate. The transition from blue to orange does not occur gradually through the spectrum because the scattering effects lead to a dominance of either blue or red light, depending on the time of day. Lower wavelengths are more likely to diffract forward, contributing to the orange sky at sunset. Additionally, phenomena such as the green flash can occur briefly at sunset or sunrise, where the sky may appear green due to specific atmospheric conditions. The presence of clouds and haze during sunset also influences the light seen, reducing blue light visibility.
Ryan Lucas
Messages
14
Reaction score
0
The sky is blue because the white light is diffused by the light particles, which scatter out the blue end of the spectrum, hense a blue sky. In the afternoon, it is often red or orange, because the light has to travel much longer through the atmosphere, scattering out the red end of the spectrum. Why then, between these two times, when the depth of the atmosphere through which the light travels increases, does our sky not change from colour to colour through the spectrum, from blue to orange? Why isn't the sky green?
 
Earth sciences news on Phys.org
The way I see it is that there will always be more red light reaching you directly than any other colour of the spectrum, and likewise there will be more blue diffracted light reaching you than any other colour. One of these two will normally dominate over the other colours. If I remember my atmosphere lectures right, lower wavelengths are more prone to diffract forwards, than higher wavelenghts that scatter more evenly, so this explains the orange sky around sunset.
Anyway, I don't know about you but I've seen some pretty nice turquoises around sunset.
 
http://www.squamish.ca/PublicDownloads/DistrictPhotoLibrary/Wallpaper/GreenSunset.jpg for instance.
 
Last edited by a moderator:
There is a phenomena known as the green flash that actually occurs shortly after sunset or before sunrise, where the sky is briefly green.
 
369025833_4eea643719_z.jpg
 
fringepringe said:
There is a phenomena known as the green flash that actually occurs shortly after sunset or before sunrise, where the sky is briefly green.
This thread has been dead for 6 years. Congrats.
 
Ryan Lucas said:
In the afternoon, it is often red or orange, because the light has to travel much longer through the atmosphere, scattering out the red end of the spectrum.
If the sky scatters blue light the sky scatters blue light. Period. Making the path longer won't make it scatter red. What happens at sunset is that you start seeing light fromthe other things besides just the sun and empty sky (clouds and haze), through a lot of sky. The light from everything you see near the sun at sunset is thus nearly absent blue light.
 

Similar threads

Back
Top