Colorful Stars

Stars come in a whole spectrum of colors, from icy blue to deep red. But our eyes can see the color in only a few stars — most of them are simply specks of white. That’s because most stars are too faint to show off their palette. The human eye can pick out the colors of only the brightest ones.

Our eyes contain two types of light receptors: rods and cones. They’re in the retina, at the back of the eye.

There are about a hundred million rods. They’re sensitive to low levels of light, so they allow us to see in the dark. But they don’t see the world as clearly as cones. And they don’t see colors.

The eye contains only about six million cones. They provide a sharper view. And they are sensitive to colors — some see red, others blue, and still others green. But they don’t activate when the light is faint. Ergo, they see the colors in bright stars, but not in faint ones.

Of course, the number of stars for which we see colors depends on the viewer. Some people have a greater sensitivity to color than others.

Most of us can see color in some of the brighter stars in view this evening. Betelgeuse, well up in the south-southwest at nightfall, is bright orange. So is Aldebaran, to its right. Rigel, below Betelgeuse, is blue-white, as is Regulus, in the east.

Some bright stars don’t show any color. The best example is Sirius, the brightest star in the night sky, which is in the south. It shines pure white — its true color.

Script by Damond Benningfield