what color is the sun

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Is it yellow because from Earth it usually looks yellow to us? Or is it white because the sun gives off all wavelengths of light (white light)? Or is it some other color?

In: Planetary Science

39 Answers

Anonymous 0 Comments

It is not yellow. It is white.

Near sunset, or when the sky is hazy, the blue end of the spectrum is scattered away to varying degrees, leaving it looking more yellow or even red. That’s because of [Rayleigh scattering](https://en.wikipedia.org/wiki/Rayleigh_scattering) for the most part, and others will give you an explanation for that.

The true spectrum of the sun from outer space is approximately a [black body radiation](https://en.wikipedia.org/wiki/Black-body_radiation) spectrum, with some deviations (because the outer opaque region of the sun isn’t of uniform temperature, and there are [absorption lines](https://en.wikipedia.org/wiki/Fraunhofer_lines) associated with hydrogen and helium, as well as some other elements.

But that’s not relevant. The sun is *by definition* white, because our eyes and brains evolved to see during the daytime, and so whatever the spectrum of the sun during daytime is *defines* white. It’s the default pattern of illumination for things that humans see.

We don’t think of the sun as white, because it is too bright to look at directly — which is good: There’s never any need to, and it means that our eyes can be sensitive to darker illumination without needing to be shielded sufficiently to look directly at the sun. The only time it’s dim enough to look at directly is when there is a lot of atmospheric scattering in the way — precisely what makes it look yellow or even red at sunset or on very hazy days.

But if you were to look at the sun on a clear day through a sufficiently dark neutral-density filter, it would just look white, because it defines, biologically and socially and developmentally, what we understand to be white.

In space it would be a tiny bit bluer.

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