• Question: Why is the sky blue???

    Asked by alex1998 to Amy, Drew, Julia, Kimberley, Sara on 15 Jun 2011. This question was also asked by crunchiejelly, rachel1995.
    • Photo: Drew Rae

      Drew Rae answered on 14 Jun 2011:

      The atmosphere itself isn’t any colour. The blue light you see when you look at the sky is light coming from the sun, but being bent around by the atmosphere to come at you from the sky. Blue light bends more than red light, so that’s the light that gets bent enough for you to see it.

    • Photo: Julia Griffen

      Julia Griffen answered on 14 Jun 2011:

      The atmosphere scatters light that has the wavelength characteristic of blue light… all the other wavelengths aren;t affected… we see the scattered blue light.

    • Photo: Amy MacQueen

      Amy MacQueen answered on 15 Jun 2011:

      Think these guys answered it! Good shout! 🙂

    • Photo: Sara Imari Walker

      Sara Imari Walker answered on 15 Jun 2011:

      Hi alex, crunchijelly and rachel!! Drew and Julia are correct!! The scattering process they describe which produces the beautiful color of our sky is called Rayleigh scattering. All atoms absorb light at different wavelengths, and they can re-emitt that light at the same wavelengths as it is absorbed. Our atmosphere is mostly made of Nitrogen which absorbs light strongly in blue wavelengths. Therefore, as light moves through the atmosphere, most of the longer wavelengths like red, orange, and yellow pass straight through. However, much of the shorter wavelength light, like blues and purples, is absorbed by the Nitrogen gas molecules (and other molecules such as oxygen!). The absorbed blue light is then re-emitted in different directions and gets scattered all around the sky. So wherever you look at our sky – blue light reaches you so the sky looks blue. This is also why sunsets look red/orange. When we look at the sky with the sun on the horizon we see light reaching us more along a straight line – so the sky looks reddish! Fun stuff =)

    • Photo: Kimberley Bryon

      Kimberley Bryon answered on 15 Jun 2011:

      The other scientists have answered this well already. Nice question though