• Question: Why is the sun yellow?

    Asked by 11wiloma to James, Marcus, Martin, Rob, Suzanne on 19 Mar 2012.
    • Photo: Suzanne McEndoo

      Suzanne McEndoo answered on 19 Mar 2012:

      Well, every light source has what we call a spectrum, which tells us how much of what frequency (colour) light comes from that source. Spectra (plural of spectrum) from stars look something like this: and one of the things that defines where the spectrum is along the line is the temperature. The horizontal line represents the frequency, how high the line goes means how much of that colour we have.

      So our sun’s spectrum looks like this The highest point of the line is around the yellow part, so we see yellow light most.

      You can also see that most of the sun’s light comes out in the visible part of the spectrum (the colours our eyes can see). This isn’t a coincidence. We evolved our eyes to use the most common light that was around us, so the light we can see is the part of the spectrum that has the highest amount of light.

    • Photo: Martin Zaltz Austwick

      Martin Zaltz Austwick answered on 19 Mar 2012:

      The sun’s colour depends on lots of complicated factors like the nuclear reactions going on, how hot it is, what chemicals in the sun absorb light, what colours are absorbed by the Earth’s atmosphere, and how the Earth’s atmosphere scatters blue light away. All of those make up the colour we see. But don’t look at the sun, it is very bright!

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