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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.

FutureSci
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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.

ChrisF
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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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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.

Adam Dai
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Our sun is white (or rather, it gives off a variety of wavelengths of light that, when combined, appear to be white.)

During sunrise or sunset it appears yellow/orange because the air, dust, and pollution cause scattering of some of the waves, leaving the yellow-orange ones.

At any other part of the day, say, high noon, the sun actually appears as its "true" colour; white. This is because the air itself is not enough to cause scattering.

Google: "sun in the sky" and "sunrise/sunset" for a comparison if you don't believe me.

People either assume or believe a misconception that the sun appears yellow because:

  • They haven't been bothered to look for themselves (either at the real sun or a photo of it at mid-day).

  • They are too scared to look for fear of damaging their eyes.

  • They have looked but they didn't pay attention to what colour it was.

  • They only pay attention to the sun during sunrise or sunset.

The reason the sun appears orange in photos for the public is because they have been altered to match what they think we think the sun looks like, which is frankly just bad, irksome and should be stopped.

Here is a video of the sun as its real colour: https://www.youtube.com/watch?v=Wi8MyCVmz6I

It hasn't been edited to make the sun yellow because editing a video takes more effort than editing a photo. Some of the light has been filtered out, however, to make it less intense than it actually is.

Frankly I'm disappointed in NASA for continuing to propagate the myth that the sun is yellow, and not, in fact, white.

user_35
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David McGhee
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If you're talking about a photo taken from Earth, then the atmosphere makes the Sun look yellow or red.

If you're talking about a lot of the photos published by NASA and others, many of the Sun photos you see are actually x-ray or infrared pictures.

To be able to see the picture, it obviously needs to be converted into something we can see. Different colours will be used to make different parts of the image stand out and easier to see. Often bright orange or red is used, but you'll also see green, blue and other colours used too.

It's also so you know the picture wasn't taken using visible light which would be a true colour image like ones taken from the ISS.

Igon Ovabord
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The Sun is white, but the reason why it is white is because your brain adjusts the white balance to make the totality of all the ambient light illuminating the objects you see, white. Now, the Sun is too bright to look directly at safely, but around dusk or dawn you can sometimes see by accident a glimpse of it, and it then looks red. So, based on the personal experience we typically have, we tend to think that the Sun is red or orange. The reason why the Sun is red at dawn or dusk is because the shorter wavelengths are scattered more, but these then still contribute to the lighting of the surroundings. So, the brain sets the white balance in the same way as it would during midday, which causes the Sun to look red. If the shorter wavelengths were absorbed instead of scattered so that they would not contribute to the lighting of the surroundings, then the Sun would continue to look white.

Count Iblis
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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

Esteban
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    Our Sun is white. Maybe Superman doesn't think so, but that's because he was born under some other Sun. If there is an objective definition of "white", it would not be, "...contains the same energy at every wavelength:" There is no such illuminant. For those of us who were born on Earth, white is the color of the light that illuminates our world at mid-day. – Solomon Slow Sep 03 '15 at 17:31