THE SUN IS NOT YELLOW!
- Dr. Teri Gee, Barlow Planetarium Director
- May 14
- 2 min read
When people draw pictures of the Sun, it almost always looks the same.
Like this --->
But the real Sun isn't yellow. It's actually white!
To explain, let's talk a little bit about light
Light has color. The light we see is part of what is called the electromagnetic spectrum. That's just a fancy way of saying light. We call the light we see visible light.
We divide that light up into colors and to remember the order, we give it an acronym ROY G BIV, which stands for:
Red
Orange
Yellow
Green
Blue
Indigo
Violet
The more energy light has, the more blue it is. The less energy it has, the more red it is. Light has primary colors, just like paint does, but they're a little different. The primary colors of light are red, green and blue. If you combine red and green, you get yellow. If you combine green and blue, you get cyan. If you combine red and blue, you get magenta. When you combine all three colors, you get white!
Back to stars
The color of a star is determined by its surface temperature. So… how does that make the Sun white? Well, most stars actually give off a lot of different colors of light. The color it gives off the most is the color we see. We say that the star's light peaks in that color. Really hot stars will look blue, while really cool stars will look red or orange. Our star (the Sun) is middle-sized. It's not really, really hot. It's not really, really cool. It's just right, and it gives off most of the colors of light nearly equally. It might have a slight yellow tint to it, but it's really mostly white.
You might be asking, "But hey, the Sun does look yellow sometimes! Why is that if it's white?" It's true, but that's not because of the Sun. It's because of our atmosphere! The atmosphere scatters blue light more easily than red light and that means we get less of the blue and more of the red mixing with green light – meaning that we get just a bit of yellow sneaking through.
No matter what color we see, the Sun gives us light and heat. Without it, life on Earth couldn't exist!
