• Question: why is the sky blue ?

    Asked by carbon to Carys, Chris, Jeremy, Katherine, Simone on 16 Jun 2011.
    • Photo: Christopher Phillips

      Christopher Phillips answered on 16 Jun 2011:

      The most popular question I ever get asked! 🙂
      The sky is blue because of sunlight. Sounds weird right?
      I’ll tell you how it works.. it’s very similar to what happens in a rainbow.
      First rays of light from the sun hit the Earth’s atmosphere (our sky).
      Then those rays of light get scattered everywhere as they bounce of atoms in our atmosphere.
      It’s like shooting bb’s from a pellet gun at a bottle. the bb’s bounce off the bottle in all directions.
      As the bounce everywhere we see a change change in colour.. that colour is blue 🙂
      When the sun rises in the morning or sets in the evening the sky turns red.. that is because the light is scattered more and more. We see that scattering as a change in colour from blue to red!
      Pretty far out eh? 🙂

    • Photo: Jeremy Green

      Jeremy Green answered on 16 Jun 2011:

      Of course, Christoper is perfectly right, but what exactly is scattering the light and why the scattered light is blue is another question.
      Interestingly, painters use this blueness effect to show perspective in their paintings: the further away something is the bluer it is. This is called “atmospheric perspective”.

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