An inverted rainbow. What a rare optical phenomenon was seen in Zaporizhzhia and how it occurs

Last week, a rare optical phenomenon was recorded in Zaporizhzhia - an inverted rainbow. It is also called a "smile in the sky".

According to the Zaporizhzhia Regional Center for Hydrometeorology, an inverted rainbow appears at an altitude of 7-8 km. This happens in the presence of cirrus clouds consisting of ice crystals.

In fact, inverted rainbows are not rainbows. The scientific name for this optical effect is the circumsensory arc, or Brave's arc. They are formed when sunlight is refracted through horizontal ice crystals at such an angle that it is decomposed into a spectrum and reflected into the atmosphere.

"They look like rainbows, and in a sense they are similar, but the fundamental difference is that rainbows are formed as a result of light bending and color separation by raindrops falling from clouds," the BBC quoted Dr. David Schultz, head of synoptic meteorology at the University of Manchester, as explaining.

The scientist says that these phenomena differ in the shape of the particles through which sunlight is refracted: "In the case of the circumsolar arc, these are hexagonal ice plates that form a cloud. In the case of a rainbow, it's a raindrop," Schultz says.

Although we don't often see inverted rainbows in the sky, circumsolar arcs are not a rare phenomenon, according to the Met Office. They occur quite often throughout the year. But they are not always visible to the human eye, as they are usually hidden behind clouds.

In order to see an inverted rainbow, a combination of atmospheric conditions must be right: the right height, depth, and position of the ice clouds, as the cloud must be at a certain convex angle to the sun. The place from where you can see the smile in the sky is also important, because its visibility can change.

Earlier, OBOZ.UA told you that the shape of the rainbow is not actually an arc. It has the shape of a complete circle, but part of this circle is blocked by the surface of the earth.

Only verified information is available in our Telegram channel OBOZ.UA and Viber. Do not fall for fakes!