Pilot’s glory is an optical sleight-of-hand that gives the impression that a plane’s shadow is illuminated by a rainbow halo. Although it would appear to be a sinister indication of supernatural influence, there is actually some science involved.
View the video that Southwest Airlines posted last month (shown below). It was captured on camera by a passenger on a commercial flight and depicts the plane’s shadow on the clouds below, which are encircled by a vivid circular rainbow. The glory seems to move with the shadow as it moves.
Pilot’s glory, also called a glory or a pilot’s bow, is made by comparable processes to those that make a rainbow, but with a unique twist.
The shadow actually plays a very minor role in the phenomenon. It just happens at the same spot as the shadow because this is the antisolar point, which is the point that seems to an observer to be directly opposite the Sun. To put it another way, the Sun is right behind the splendor of the viewer and its shadow.
Water droplets above the cloud scatter sunlight back toward a light source, creating the rainbow’s colors.
The truth is that there is still some debate among scientists over how glories are created, and the ideas are somewhat complicated.
We are aware that they do, however, show up in a variety of other situations. When the sun was directly behind them, climbers may occasionally see the glory when they peered down a mountain at their own shadow.
A group of French explorers scaling the Peruvian Andes provided one of the earliest descriptions of the occurrence in 1735. “A phenomenon that must be as old as the world, but that no one seems to have observed thus far,” they write. The thing that struck us as most amazing was the way the head appeared to have a halo or glory surrounding it, made up of three or four little concentric rings that were all extremely brightly colored, each with the hues of the primary rainbow, with red being the furthest.
They also note another odd aspect of it, which is interesting to note: “The most remarkable thing was that, of the six or seven people that were present, each one experienced the phenomenon just around the shadow of his own head, and saw nothing around other people’s heads.”