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Rainbow Skies

What colour is the sky? The answer depends on when you look at the sky. Sometimes it looks blue, sometimes it’s orange and sometimes it’s red or purple. In fact, the sky is really many colours at once, but human eyes can only see certain colours at certain times.

The light that travels to Earth from the sun looks white. But hidden inside that white light are all the colours of the rainbow. The gases around Earth, which make up its atmosphere, break up the sun’s light. This makes the light bounce around in different directions. Scientists call this scattering. Blue light is one of the colours that scatters the most. It is also a colour that is easy for our eyes to see. For these reasons, blue is the colour we see most often in the sky.

At sunrise and sunset, the sun is lower in the sky. This makes the light scatter differently, so we can see different colours. During sunrises and sunsets, colours like yellow, orange and red are easier to see. Those beautiful colours are always there, but they are only visible when the sun is low.

Natural events, such as clouds passing or even a volcano erupting, can make the sunset even more colourful. As the sun goes down, clouds and ash high in the sky catch the sunlight and scatter it in different ways. This scattering can show off even more colours. When this happens, beautiful pinks and purples often fill the sky.