Why is the sky blue


The sky appears blue during the day because the blue light from the sun is scattered much more than other colors due to its shorter wavelength and smaller waves[2]. The blue light travels in all directions and reflects off of particles in the atmosphere, while the red and orange light travels towards us since it has not been scattered much[1]. Water appears blue due to the absorption of the red light, which is why oceans and lakes appear blue when the sun is out[7].

This scattering of the blue light is what gives the sky its bright blue color[2].


  1. https://spaceplace.nasa.gov/blue-sky/en/
  2. https://www.rmg.co.uk/stories/topics/why-sky-blue
  3. https://www.mcgill.ca/oss/article/environment-general-science-you-asked/why-sky-blue-or-better-yet-why-ocean-blue
  4. https://scijinks.gov/blue-sky/
  5. https://math.ucr.edu/home/baez/physics/General/BlueSky/blue_sky.html
  6. https://www.space.com/why-is-the-sky-blue
  7. https://www.sciencemadesimple.com/sky_blue.html
  8. https://www.scientificamerican.com/article/why-is-the-sky-blue/
  9. https://www.metoffice.gov.uk/weather/learn-about/weather/optical-effects/why-is-the-sky-blue
  10. https://mysterydoug.com/mysteries/sky-blue

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why is the sky blue
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why is the sky blue
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why is the sky blue
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why is the sky blue
Source: math.ucr.edu