• Question: why is it when you look at the sun it turns bluey green

    Asked by yousmileismilem0195 to Meeks, Pete, Stephen, Steve, Tom on 19 Jun 2010 in Categories: .
    • Photo: Steve Roser

      Steve Roser answered on 18 Jun 2010:

      You should never look at the sun straight on – its too bright. When you can see is when you look at it thru a lot of atmosphere – last thing at night. The light coming from teh sun is a mixture of all colours – blue light is scattered more than red light (so the sky is blue from teh scattered light during the day) at dusk all the blue light is scattered away and so the sun looks red until it just goes down and just above the horizon you can see teh last bit of scattered light – which is bluey….

    • Photo: Marieke Navin

      Marieke Navin answered on 18 Jun 2010:

      you should never ever ever look at the sun!!

    • Photo: Tom Hartley

      Tom Hartley answered on 18 Jun 2010:

      Don’t look at the sun – you can very easily damage your eyes. The bluey-green afterimage is caused by adaptation of the photoreceptors (so you see the “opposite” colour to the orangey-yellow sun, I believe. Too much sunlight focussed on the retina will damage it irreparably. So please don’t look at the sun on purpose.

      There are special filters you can get to look at the sun e.g., during an eclipse, but even then be very careful and take advice from an expert.

      I saw a total eclipse of the sun in Amiens back in 1999 and it was truly awesome (I use the word very advisedly); if you ever get the chance to see one you should take it, even if it means a long detour, as it did for me.

    • Photo: Stephen Curry

      Stephen Curry answered on 19 Jun 2010:

      OMG – don’t look at the sun! It’s way too bright and could damage your eyes. I guess if you squint at it between nearly-closed eyelids, it might be OK for short periods.

      But I have to say I have never noticed the blue-green coloration that you describe. Can you say more about the exact conditions of your observation?

      The sun itself appears white since it emits all the colours of the visible spectrum (plus UV and infrared) – The spectrum of light that it emits is centred on wavelengths of about 500 nm, which is yellow.

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