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The Sun Only Looks Yellow To Human Eyes—So What’s Its True Color?
By Alexa Heah, 21 Sep 2021
Image via Shaun Jeffers / Shutterstock.com
Even though we’ve been coloring the Sun with a yellow crayon ever since arts and crafts in preschool, our closest star may not be that color after all.
The Sun gives off light over an entire range of wavelengths, which make up the different colors we see. A star’s peak wavelength usually determines what color it gives off, for example, cooler stars may appear red while hotter stars may appear blue.
According to Dr Alastair Gunn for Science Focus, it seems that the Sun’s peak wavelength would actually make it appear green. How come we don’t see it as a green orb?
Firstly, humans can only perceive a small part of the light spectrum, and the sun emits the same amount of light at each wavelength, causing us not to notice the difference. Plus, our eyes don’t register the color of something by finding the average of its wavelengths.
In this case, a slight green tinge would just come off as white to us on Earth. For us to see the Sun as green, it’d have to emit only green light for our eyes to pick it up as such.
Then the next question… if the Sun is white, why does it appear yellow our whole lives?
This is due to the Earth’s own atmosphere, which happens to disperse more blue light than red light. The slight imbalance between the two causes us to see the sun as yellow.
But if you’ve noticed, the Sun occasionally looks more reddish during sunrises and sunsets, because more blue light is being scattered by the atmosphere, introducing a little more red to our gaze.
While it’d still be difficult to convince someone that the Sun’s actually white—or, more accurately, green—it’s a great bit of trivia to have for that post-pandemic pub quiz.
[via Science Focus, cover image via Shaun Jeffers / Shutterstock.com]
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