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I was thinking about elementary physics today and realised: We learned and proved that sunlight is white. But i don't understand why when you look at a picture of a satellite orbiting the sun , it(the sun) seems yellow-orrange. How could this be? It is like there is a red light bulb in the room but what you see is green.

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One possibility: the colors from the camera on the satellites are not exactly detected as our eyes do. –  fffred Aug 21 '13 at 21:28
    
Following ChrisF's comment, do you mean a photograph taken from the satellite, or containing the satellite? –  fffred Aug 21 '13 at 22:03
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It may involve "light balance". –  jinawee Aug 21 '13 at 22:04
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How did we prove that sunlight is white? –  Asphir Dom Aug 21 '13 at 22:25

3 Answers 3

Most pictures of the Sun that you see online are taken in infrared, and the color scale is most likely not true to visible light.

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That's because our sun is not white. The color of stars indicate how hot they are running. With different temperatures, the stars are creating different elements by fusion. I'm a little rusty on my astrophysics to expand more, but here are some links that might be of interest to you: http://docs.kde.org/stable/en/kdeedu/kstars/ai-colorandtemp.html http://en.wikipedia.org/wiki/Stellar_evolution http://www.youtube.com/watch?v=4s7vyDLgk3M

And a documentary from Discovery: http://www.youtube.com/watch?v=lir0k8xY0DQ

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The main reason why the sun doesn't look white is due to Rayeleigh Scattering means that the blue light from the sun is scattered so it appears to be yellow or even orange when viewed through thicker atmosphere.

This means that when you take a photograph of the sun (through the necessary filters) from the surface of the earth it will appear yellow or even orange.

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I believe the question is about pictures from a satellite, not taken through atmosphere. –  fffred Aug 21 '13 at 21:59
    
@fffred - Hmm. The question isn't clear. I thought that the satellite mentioned in the question is in the photo rather than taking the photo. –  ChrisF Aug 21 '13 at 22:01
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Well, good luck making a picture of a satellite in orbit from inside the atmosphere (deep enough for Rayleigh scattering to have a noticable yellowing effect)! But even without atmosphere – a picture of a satellite and the sun together, where the latter isn't overexposed on all color channels (and thus white, regardless of its "actual color") is unlikely to be real. –  leftaroundabout Aug 22 '13 at 18:30
    
@leftaroundabout - indeed now you mention it, it would be hard, but not impossible. –  ChrisF Aug 22 '13 at 21:00

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