In some stage of our lives, we have inevitably drawn the Sun as a yellow circle. In fact, if we study the design of many flags and coats of arms, the Sun appears in that color. However, different publications recommend we reinterpret the Sun, or rather, the way we see its light. Why? Because yellow is not the predominant color, and its “peak” is located in the green…
One of the first things we must understand about color is that it does not exist. In other words, it is not an inherent property of matter, or as the latest video published by the SciShow channel suggests, color “is in our brains, not in the world”. For example, black is not black, but rather what your brain interprets in the absence of light. But light does exist, and in different wavelengths. How is that light generated? What does temperature have to do with it? Why should we accept a crazy title like “the Sun is green”? Well… it's complicated.
Why It’s Believed the Sun Is Green
Just like with all matter, the Sun emits what is known as a “blackbody spectrum”, defined by the temperature of its surface. A quick Google search indicates that the Sun’s surface temperature is very close to 6,000 Kelvin. Stars with these parameters deliver most of their energy in the infrared, even though their intensity peaks are located in the visible spectrum. Where is the maximum? At a wavelength of 500 nanometers… and that gives us green.
The “blackbody curves” of different stars (NASA, ESA, Leah Hustak (STScI), Andi James (STScI))
However, not everyone agrees with that interpretation. An article published in Big Think warns us that associating the peak wavelength with a color is incorrect, and reminds us that color does not exist independently of human perception. Sunlight contains many other colors besides green, and if we remove all potential interferences (including our own atmosphere), the result is white. The problem is that this clashes with articles published by NASA itself. So, what is the correct answer? I think the SciShow video sums it up well: The Sun is yellow, it is white, it is green, and it is infrared.
Sources: NASA, Big Think
