Solargoods's Blog

What Color Is The Sun?

Have you ever consider this question before when you see the sun?

Someone says that the Sun has a spectral type of G2V. Its color is yellow. But although the Sun gives off most of its energy in the yellow-green frequencies, the light emitted is effectively white. The yellow color and apparent texture come from the scattering of its light by Earth’s atmosphere. This is evident in photographs from space. The actual granulation is invisible except under magnification, and sunspots are not discernible as ‘darker’ by the human eye (this requires heavy filtering).
This question allows us to explore two different aspects of what we call “color”. The quick answer, for anyone who doesn’t want the detailed explanation, is that the sun is a “yellow” star by definition, regardless of where you are, but, if you look at it in space it would be so bright that it would appear white.

The first has to do with physics and the nature of the light coming from the object you’re observing, and the second has to do with physiology and how your eyes and brain perceive that light. When something emits light evenly across the entire visible spectrum (for example, there are equal amounts of red, blue, yellow and green light), we call that light “white”. Our sun’s light, though really spread across many colors, peaks in the yellow range; this is true whether or not you have the atmosphere between us and the sun.

Your eyes don’t see the actual color of the light waves it receives. Instead, it has three types of “photo receptors”, which produce a neural response when they intercept light of specific colors. The receptors are called “red” “green” and “blue”, although those names are something of a misnomer. Any of them can detect most light that comes in. However, they each produce their strongest response when the light they “see” is closest to their color.

Another effect that may come into play is contrast detection. Your brain, after the eye does the red-green-blue color processing, tries to compare nearby colors against each other. Your brain compares white vs. black, red vs. green, and yellow vs. blue.

The sun’s actual light is mostly white, with a little yellow.