Why Does the Sky Appear Red at Sunrise/Sunset?

In summary, the sky appears blue during the day due to the scattering of blue light with shorter wavelengths. However, during sunrise and sunset, the sky appears red because at lower angles, there is more atmosphere for the light to pass through, causing more scattering of shorter wavelengths and leaving only longer wavelengths (such as red) to reach our eyes. Although air is transparent, it still affects the light coming from the sun. Additionally, the sky appears blue and not violet because our color receptors have a tendency towards blue over violet.
  • #1
AlchemistK
158
0
I know that the sky appears blue because the blue light gets scattered the most due to its high frequency(according to Raleigh's law) but then during the sunset or sunrise, why does the sky appear red? Doesn't almost all of the blue light get scattered , and maybe just a small portion of red? Then why does the sky appear more red than blue?
 
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  • #2
As I understood it:
Lower angle, more atmosphere to pass through, more scattering of shorter wavelengths, which in turn leaves only the longer(read: RED) wavelengths free to reach your eyes.
 
  • #3
Isn't it supposed to be that the light that gets scattered forms the color of the sky rather than the light left from the sun? Because during the day,as i know it, the blue light gets scattered and the sky appears blue and the rest reaches our eyes as it is.
 
  • #4
Consider the meaning of scatter :)
However transparent, air is still matter and has an effect on the light coming from the sun.
When a coherent beam hits the atmosphere, it gets scattered in all direction which means each molecule gets to "shine" with whatever color/wavelength it's diffusing.
At shorter atmospheric traveling distances shorter wavelengths are scattered and the sky shines blue, at longer distances it gets orange and red.

While we are on the subject, there is another mystery as well - why is it that the sky is blue and not violet, considering it is the shortest visible wavelength. :)
 
  • #5
Oh. I know that, the problem of us not seeing the sky violet is because of the the colour recptors in our eyes, they have a tendency towards blue more than violet, hence the sky appears more of a shade of blue. Atleast this is what i read somewhere.
 

1. Why does the sky appear red at sunrise and sunset?

During sunrise and sunset, the sun is positioned at a low angle in the sky. As sunlight passes through the Earth's atmosphere, it interacts with particles such as dust, water droplets, and pollutants. These particles scatter the sunlight and filter out shorter blue and green wavelengths, leaving behind longer red and orange wavelengths that give the sky its red appearance.

2. Is the sky always red at sunrise and sunset?

No, the sky can appear different shades of red, orange, pink, and purple during sunrise and sunset. This depends on the amount and type of particles present in the atmosphere, as well as the angle and intensity of the sunlight.

3. Why does the sky sometimes appear more vibrant during sunrise and sunset?

When the atmosphere has a higher concentration of particles, such as after a storm or in a heavily polluted area, the sunlight is scattered and reflected more intensely. This results in a more vibrant and colorful display during sunrise and sunset.

4. Can the sky appear red at other times of the day?

While the sky is typically red during sunrise and sunset, it can also appear red during certain weather conditions such as a dust storm or wildfire. In these cases, the particles in the atmosphere are being carried by air currents and can create a red or orange tint to the sky.

5. Does the color of the sky during sunrise and sunset have any significance?

In some cultures, the color of the sky during sunrise and sunset is seen as a sign of good luck or a blessing. It is also a popular time for photographers to capture beautiful and dramatic images. However, scientifically, the color of the sky during sunrise and sunset is simply a result of the Earth's atmosphere and the position of the sun.

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