• Question: Why is the sky blue?

    Asked by 228mutg29 to Emma, Monica, Sebastian, Sinead, Thomas on 8 Nov 2016.
    • Photo: Emma Roycroft

      Emma Roycroft answered on 8 Nov 2016:

      Well I’m not exactly sure since I am not really a physics expert but I think it is something to do with how water molecules in the atmosphere act like prisms. They mostly emit the blue light in daytime, but as the earth moves during the day, the red and yellow lights are emitted more at sunset.

    • Photo: Sebastian Gornik

      Sebastian Gornik answered on 8 Nov 2016:

      Hi,

      Cool question, and something I had to look up myself too :-).

      Basically, to explain in simple terms: tiny tiny particles and molecules in the air interact with sunlight. Sunlight itself has many colours which together make what we call daylight. The molecules and particles in the air reflect and break the colours in sunlight in various ways. During the day, when the sun is high in the sky, these interactions emphasize the blue light component of sun light much more so than the other colours and thus the sky appears blue. At dusk and dawn the different angle of the sun causes its light rays to interact differently with the molecule sin the air causing the red-ish components of the sun light to be more emphasized, thus we see the sky as orange and red.

      This is however just the simplest version and there is much more advance physics hidden in this process.

      See a nice and slightly more detailed explanation here:

      http://spaceplace.nasa.gov/blue-sky/en/

      Enjoy!

    • Photo: Sinead Loughran

      Sinead Loughran answered on 8 Nov 2016:

      It’s gas.
      Literally.
      As the other have said the sky is blue because of what happens light waves as they travel through the atmosphere of gas.

      Blue light (from the sun) is absorbed by gas molecules and then radiated in different directions. It gets scattered all around the sky. Whichever direction you look, some of this scattered blue light reaches you. Since you see the blue light from everywhere overhead, the sky looks blue.

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