Rayleigh scattering causing blue skies

In summary, the conversation discusses the concept of why the sky appears blue when the atmosphere absorbs and scatters blue light. Despite the overlapping of other unabsorbed colors, the excess of blue light is still significant. The conversation also considers the paths of different wavelengths from the sun to the eye.
  • #1
sgstudent
739
3

Homework Statement


The atmopshere allows all the colours of white light except the blue one and instead absorbs it. It is then scattered as blue light. However, I don't get why we would see it as blue. Won't the scattered light overlap all the other colours that were not refracted? So shouldn't the sky appear white?


Homework Equations



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The Attempt at a Solution



The only reasoning is that the blue light is so much greater that even after overlapping the other unabsorbed colour of light (to make it white) there's still some excess. But this also doesn't make sense as the amount of blue waves will be equal to the other colours as white light enters our atmosphere.

Thanks for the help!
 
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  • #2
Consider the paths taken by by different wavelengths from the sun to your eye. (What colour does the sun appear to be?)
 

1. What is Rayleigh scattering and how does it cause blue skies?

Rayleigh scattering is a phenomenon that occurs when sunlight interacts with particles in Earth's atmosphere, such as nitrogen and oxygen molecules. The particles cause the sunlight to scatter in all directions, with shorter wavelengths (such as blue and violet) being scattered more than longer wavelengths (such as red and orange). This results in the blue light being scattered and dispersed throughout the atmosphere, making the sky appear blue to our eyes.

2. Why does the sky appear red or orange during sunrise and sunset?

During sunrise and sunset, sunlight must travel through a larger portion of Earth's atmosphere before reaching our eyes. This causes more scattering of the shorter wavelengths, leaving mostly longer wavelengths (such as red and orange) to reach our eyes. This is why the sky appears red or orange during these times.

3. Does Rayleigh scattering only occur in Earth's atmosphere?

No, Rayleigh scattering can occur in any medium that contains particles that are smaller than the wavelength of the incoming light. This includes other planets' atmospheres, as well as the Earth's oceans and even certain types of glass.

4. How does pollution affect Rayleigh scattering and the color of the sky?

Pollution, such as smog and haze, can scatter and absorb sunlight in different ways than natural particles in the atmosphere. This can affect the amount of blue light that is scattered and the overall color of the sky. In areas with high pollution levels, the sky may appear more gray or hazy instead of a vibrant blue.

5. Can Rayleigh scattering cause other colors in the sky besides blue?

Yes, although blue is the most commonly observed color due to the shorter wavelength of blue light, Rayleigh scattering can also cause other colors in the sky depending on the conditions. For example, during a volcanic eruption, particles from the ash plume can scatter sunlight and cause the sky to appear red or orange.

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