• Question: why is the sky blue?

    Asked by chloefernee to Hannah, Ian, Jono, Mark on 26 Jun 2013. This question was also asked by ethanrich.
    • Photo: Ian Wilson

      Ian Wilson answered on 26 Jun 2013:

      Hi Chloe,

      This is a great question – the sky should be black shouldn’t it, because space is black?

      When the light from the Sun reaches Earth’s atmosphere, it hits all of the gas molecules and dust particles in the atmosphere. This makes the light scatter off in all directions, rather than always coming straight down to Earth. It’s kind of like when you shine a white light into a prism and the light comes out in a rainbow. The light from the sun is being refracted so it looks blue. The scattering of light like this is called ‘Rayleigh scattering’, after the scientist who discovered it.

      Hope that makes sense,

      Ian

    • Photo: Hannah Brotherton

      Hannah Brotherton answered on 26 Jun 2013:

      Hi Chloefernee,
      The light from the Sun looks white. But it is really made up of all the colors of the rainbow. Light travels in a straight line, unless it is bent or reflected or scattered by something.

      Sunlight reaches Earth’s atmosphere and is scattered in all directions by all the gases and particles in the air. Blue light is scattered in all directions by the tiny molecules of air in Earth’s atmosphere. Blue is scattered more than other colors because it travels as shorter, smaller waves. This is why we see a blue sky most of the time.

      But sometimes we get red skys at dusk…why?

      As the Sun gets lower in the sky, its light is passing through more of the atmosphere to reach you. Even more of the blue light is scattered, allowing the reds and yellows to pass straight through to your eyes.

      😀

    • Photo: Jono Bone

      Jono Bone answered on 27 Jun 2013:

      Hi Chloe,

      This is a question that has puzzled many people throughout history.

      The light from the Sun looks white. But it is really made up of all the colors of the rainbow. Light travels in waves.When the light waves from the sun enter earths atmosphere they are scattered in all directions by all the gases and particles in the air. Blue light travels as shorter, smaller waves than the other colours and so is scattered more than other colors and this is why the sky looks blue.

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