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

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Discussion Overview

The discussion centers around the phenomenon of why the sky appears blue while the sunlight that reaches the Earth is perceived as white. Participants explore the interactions of sunlight with the Earth's atmosphere, particularly focusing on scattering and refraction processes.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification

Main Points Raised

  • One participant, Jacob, questions why the sky is blue if the light reaching the Earth is white, suggesting a possible "super-refraction" effect in the atmosphere.
  • Another participant points out that while the explanation for the blue sky is understood, it seems to imply that red light is scattered randomly, which raises further questions about the behavior of light through a prism.
  • A different participant notes that if the atmosphere were thicker, the sun would appear red, particularly at sunset, indicating that the scattering of light is dependent on atmospheric thickness.
  • It is mentioned that although blue light is scattered more, the overall scattering is not sufficient to alter the perceived color of sunlight significantly.
  • A reference to a more formal explanation is provided, suggesting that there are additional resources available for deeper understanding.

Areas of Agreement / Disagreement

Participants express varying levels of understanding and curiosity about the topic, with some agreeing on the scattering effects while others raise questions about the implications of those effects. The discussion remains unresolved regarding the specific mechanisms that lead to the observed phenomena.

Contextual Notes

Participants have not fully explored the assumptions behind the scattering processes or the definitions of color perception in relation to atmospheric conditions.

wasteofo2
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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 a lot,
Jacob
 
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Alright, so that said why the sky appeared blue, but it would seem from that explanation that the red light from the sun was shot off in some random direction, yet when you shine sunlight through a prism, you get all the colors...
 
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.
 
A more formal explanation can be found/derived from here
 

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