Haidinger fringes

Haidinger fringes are colorful patterns that you might see when you look at a bright light or a blue sky. They look like tiny rainbows, but they are actually caused by the way light waves interact with your eyes.

Imagine you are standing outside and you look up at the sky. You might see a blue color that fills your entire field of view. But if you look closer, you might see very thin lines or stripes of color that seem to radiate out from the center of your vision. These are the Haidinger fringes.

The fringes are caused by a property of light called polarization. Light waves can vibrate in different directions, and when they interact with certain materials, they become polarized - meaning they all vibrate in the same direction.

In the case of the sky, sunlight is scattered by the atmosphere, and the resulting light waves are polarized in a particular way. When these polarized light waves enter your eye, they interact with the natural polarization of the eye's lens and retina, creating the Haidinger fringes.

The fringes usually appear as a pair of interlocking, diamond-shaped patterns with a yellowish tint. They are named after Wilhelm Karl von Haidinger, an Austrian mineralogist who discovered them in the 19th century.

Even though Haidinger fringes are caused by a scientific phenomenon, they are not harmful to your eyes and are usually just a curious visual effect. So next time you see them when you look up at the sky, you can impress your friends with your knowledge of polarization and Haidinger fringes!