• Question: why is the sky blue?

    Asked by kkfbmm to Donna, Jo, Mark, Stuart, timcraggs on 24 Jun 2010 in Categories: .
    • Photo: Donna MacCallum

      Donna MacCallum answered on 22 Jun 2010:

      All to do with sunlight refraction and how we perceive it here on the earth’s surface

    • Photo: Joanna Buckley

      Joanna Buckley answered on 22 Jun 2010:

      Hiya kkfbmm 🙂

      It’s due to Rayleigh scattering. As light moves through the atmosphere, most of the longer wavelengths pass straight through, things like red and orange.

      However, much of the shorter wavelengths of light are absorbed by the gas molecules and gets scattered all around the sky. Whichever direction you look, some of this scattered blue light reaches you.

      🙂

    • Photo: Mark Lancaster

      Mark Lancaster answered on 22 Jun 2010:

      Because the upper atmosphere scatters the blue components of the sun’s light towards us – the higher wavelengths are not scattered so much. The blue light gets scattered because it’s of the correct energy to be absorbed and then re-emitted by molecules in the upper atmosphere

    • Photo: Tim Craggs

      Tim Craggs answered on 24 Jun 2010:

      It is because the shorter wavelengths of light are scattered more by the atmosphere, so it looks blue.

      The sunlit sky appears blue because air scatters short-wavelength light more than longer wavelengths. Since blue light is at the short wavelength end of the visible spectrum, it is more strongly scattered in the atmosphere than long wavelength red light. The result is that the human eye perceives blue when looking toward parts of the sky other than the sun. (from wiki!)

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