Cast your mind back to when you were a little kid and you would scribble a yellow Sun in the corner of each of your drawings. Or how about in high school when you’d flick through your science textbook and see the sun printed as an
Cast your mind back to when you were a little kid and you would scribble a yellow Sun in the corner of each of your drawings. Or how about in high school when you’d flick through your science textbook and see the sun printed as an orangey-yellow and red ball of light.
Well, it seems like such a stupid question to ask what color the Sun is, especially when we look up to the sky and it appears as a yellowy-orange. However, have you ever actually wondered what color the Sun actually is, without looking directly at it?
It seems that there are many correct and different answers to this seemingly simple question. In this article we’re going to look at some of these answers, and why the Sun appears as certain colors during different times of the day.
Let’s get started!
What Is The Actual Color Of The Sun?
As humans, our perception of color is influenced by both the wavelength and intensity of the emitted light, as well as the limitations of our eyesight, environmental factors, and our brains.
To determine the color of a star, both the surface temperature and the wavelength that the human eye can perceive will come into play.
The Sun emits light over a variety of wavelengths (otherwise known as colors). Apart from gamma rays, the Sun emits light across all parts of the electromagnetic spectrum.
As with all matter, the Sun emits a “black body spectrum”, which is defined by its surface temperature. For the Sun, this black body spectrum is a bell-shaped curve that involves electromagnetic (EM) radiation at various different wavelengths, from long infrared to short ultraviolet.
When there are extremely explosive and high-energy solar flare events, the Sun emits an extremely large amount of x-ray and gamma-ray radiation. These solar flares are a result of a sudden release of magnetic field energy which accelerates charged particle plasmas.
This all sounds a little confusing, but what it does show is that the Sun emits energy at all wavelengths, which means that it can produce all colors across the spectrum.
However, the Sun emits most of its energy around 500 nm, which is close to green-blue light. This means that some people would actually classify the Sun as blue-green.
This is because the Sun’s radiation frequency is governed by its surface temperature – which is around 5,780 Kelvin.
A higher surface temperature would have a shorter maximum wavelength, which means that the Sun would peak in the blue or violet (or even the ultra-violet) part of the spectrum.
If the Sun had a lower surface temperature, then its spectrum would peak in the yellow, orange, or even red part. So, by that logic, cooler stars appear to be red, and hotter stars appear blue. Orange, yellow, and white stars have a surface temperature somewhere in between.
However, this is physics and not perception. The human eye doesn’t perceive light by averaging the various colors of the spectrum together. Therefore, a very slight green light doesn’t look green to the human eye, which makes the Sun look white.
For our eyes to be able to perceive the Sun as green, it needs to emit only green light.
Why Does the Sun Look Yellow?
As we’ve established, where the Sun’s energy emits on the spectrum is closest to the green-blue color. However, the 