Why Some Planes Leave Behind Colorful Trails in the Sky

No matter where you find them, rainbows are just plain magical. Especially when they’re being trailed off the back of an airplane.

According to the Daily Mail, German photographer Nick Beyersdorf, also known as Reddit user TheFox720p, captured a Qatar Airways A380 plane dragging a peculiar cloud of rainbow-colored trails as it was flying over Bamberg, Germany on Monday.

Before you jump to conclusions, the strange contrails are not the work of a government conspiracy, Photoshop, or even a tribute to Pride month. Instead, these colorful contrails are actually a natural phenomenon that can be captured by aviation photographers if they’re in the right place at the right time.

“I was in the garden with my mother and I got my camera with me because I saw a Qatar Airways plane appearing over the neighbor’s house,” Beyersdorf told the Daily Mail. “It wasn't starting like normal contrails from the engines but from the wings. So I took quite a few pictures. Due to the angle of the sun, the contrail started to get rainbow colors.”

In order to understand why these contrails are so colorful, it's important to realize that contrails are mostly made of crystalized or frozen water vapor, which is a byproduct of jet engine combustion. Usually, contrails appear white in the sky, sometimes lingering for hours if the air is humid enough.

These water droplets can also sometimes reflect and refract sunlight, causing a rainbow effect. When it happens to regular clouds, it’s simply called cloud iridescence.

According to Contrail Science, this iridescent contrail is also called an aerodynamic contrail. This happens when air pressure and temperature over the wings drop dramatically, causing the water vapor to freeze at different sizes. These frozen water droplets refract the light at different wavelengths, which looks to us like a rainbow.

Ever shined a light through a clear prism in school? That’s how it works.

According to Contrail Science, this kind of contrail is more common in warm, humid weather since there needs to be enough moisture in the air.

Next time you’re close enough to a plane taking off on a warm, humid day, it might be worth it to look up.