• Question: Why is the sky blue?

    Asked by maggie246 to Ed, Sam, Steve, Vera on 22 Jun 2011. This question was also asked by cookieland.
    • Photo: Vera Weisbecker

      Vera Weisbecker answered on 22 Jun 2011:

      The standard answer is that the sky is blue because blue has a really short wavelength and for that reason gets scattered more by the molecules that constitute the air. The more a colour gets scattered, the more of it you see in the atmosphere – this is why the sky appears blue.

      But I remember from physics at Uni that the actual physical explanation is so complicated that people still don’t quite get the mechanism behind this scattering…

    • Photo: Steven Daly

      Steven Daly answered on 22 Jun 2011:

      Vera is right, blue light is much more likely to be absorbed by molecules in the air, and then it will be re-emitted in all directions. The same kind of reason is why the sky is red at sunset, but this time it is light scattering of dust particles in the atmosphere. Because dust is larger than a molecule it will interact more with red light, and scatters that instead.

      Vera is right in saying that the full mechanism behind it is very complicated, but it is infact related quite closely to what I do in my research!

    • Photo: Ed Morrison

      Ed Morrison answered on 22 Jun 2011:

      You mean it’s not just blue paint on the inside of the glass dome above us?

      Who knew?

    • Photo: Sam Tazzyman

      Sam Tazzyman answered on 22 Jun 2011:

      That’s cool that people still don’t really get the scattering mechanism – I didn’t know!

Comments