Why is the sky blue yet the light that reaches the earth white?

In summary, the conversation discusses why the sky appears blue despite the fact that the light reaching the Earth's surface is white. The explanation given is that the Nitrogen in the Earth's atmosphere refracts the white light and makes blue more visible. However, it is still unclear why the light reaching the Earth's surface is white if blue is more visible. It is suggested that there may be some form of super-refraction happening in the atmosphere, but this is not confirmed. The conversation ends with a request for a more thorough explanation and the mention of a website that provides a more formal explanation.
  • #1
wasteofo2
478
2
I've never been able to get an answer as to why is the sky blue yet the light that reaches the Earth white. I've been told that the Nitrogen in the Earth's atmosphere refracts the white light coming from the sun in a way that makes blue more visible. That's fine, however, what I can't understand, is if somethign up in the atmosphere is making blue more visible, why the light that reaches the Earth's surface is white. The best I can do is guess that there's some super-refraction going on up high in the atmosphere and somehow the refracted wavelengths re-combine with the other wavelengths of light on the trip to Earth's surface, but that's probabally wrong.

Can anyone try to explain this to me?

Thanks alot,
Jacob
 
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  • #2
  • #3
Alright, so that said why the sky appeared blue, but it would seem from that explanation that the red light from teh sun was shot off in some random direction, yet when you shine sunlight through a prism, you get all the colors...
 
  • #4
The web page pretty much explained it. If the atmosphere were thicker, the sun would look red, and in fact at sunset when the light has to travel through a lot of air, the sun does look red.

The atmosphere is thin enough that normally, though blue light and higher frequencies are scattered "more", there's not enough scattering to significantly change the color.
 
  • #5
A more formal explanation can be found/derived from here
 

What causes the sky to appear blue?

The sky appears blue because of the way sunlight is scattered in the Earth's atmosphere. The molecules in the air scatter sunlight in all directions, but blue light is scattered more than other colors because it travels as shorter, smaller waves. This is known as Rayleigh scattering.

Why is the light reaching the Earth white if the sky appears blue?

The light reaching the Earth is actually a combination of all the colors of the spectrum, including blue. However, our eyes perceive it as white because all of these colors are blended together. This is why we see the sky as blue during the day and as a mixture of colors during sunrise and sunset.

Does the sky's color change at different times of the day?

Yes, the color of the sky can vary throughout the day due to changes in the angle of the sun and the amount of particles in the atmosphere. At sunrise and sunset, the sky appears more orange or red because the sunlight has to pass through more of the atmosphere, which scatters out the shorter blue wavelengths.

Why does the sky appear darker at night if the sun is still shining?

During the day, sunlight scatters off the particles in the atmosphere, making the sky appear bright. However, at night, when the sun is no longer directly overhead, the light has to travel through more of the atmosphere to reach our eyes, resulting in less light reaching us and making the sky appear darker.

Does the sky's color change in different parts of the world?

The color of the sky may appear slightly different in different parts of the world due to variations in atmospheric conditions and the position of the sun. For example, the sky may appear more vibrant and blue in regions with less air pollution, while areas with more pollution may have a slightly grayer or hazier sky. However, the overall phenomenon of the sky appearing blue is consistent across the globe.

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