Buzz
If you take a closer look at the night sky, you'll observe that stars vary greatly in shape and size. While white is the dominant color, stars also shine in blue, red, and yellow hues. However, no matter how long you peer through a telescope, you'll never spot a green star. This doesn't mean that stars can't emit green light—it’s just that our eyes interpret the light differently.
Just like flames, stars change their appearance depending on their temperature. The coolest stars radiate red, while the hottest ones appear blue. But stars don't glow in just one color. Instead, they emit a range of light wavelengths, each corresponding to a different color. Our eyes can’t distinguish every individual wavelength. Instead, we perceive the color that has the strongest wavelength. If you were to graph the wavelengths of a star's light, it would form a bell-shaped curve, with cooler stars peaking in red and hotter ones peaking in blue.
So, where do green stars fit into the picture? Stars with medium temperatures mostly emit green light, but they don’t actually appear green. The light wavelength curve for these stars peaks in the green zone, which sits in the middle of the spectrum. However, because they also emit significant amounts of red, yellow, and blue light, our eyes combine all these colors and process them as white. That’s why stars like our sun, which have average temperatures, appear white—it's not because they're particularly hot or bright, but because their color is the result of a balance of wavelengths.
You won’t spot purple stars in the sky either. This is because our eyes are more sensitive to blue light than purple, and stars that radiate purple also give off a considerable amount of blue light, which is next to purple on the color spectrum.
To discover more about the reasons behind a star's glow, explore these facts about the sun in our solar system.
