Unique rainbow clouds were observed in the Arctic for three days in a row

Due to the extremely sharp cooling of the upper atmosphere, the sky over the Arctic has turned the color of a rainbow. This optical phenomenon lasted for 3 days and, according to experts, may be repeated over the next three months.

The polar stratospheric clouds were seen from December 18 to 20 in the skies over Norway, Sweden, Finland, Alaska and Scotland. In some cases, such shimmering was seen on December 21, but now the glow is disappearing, Live Science reports, citing Spaceweather.com.

Photos of this "pearly sky" were shared by eyewitness Ramunė Šapailaitė on her Facebook page. It is noted that such a rare photo was taken in the city of Grane, in the south of Norway. According to Ramunė Šapailaitė: "The clouds were visible in the sky all day, but the colors really exploded just before sunset."

According to Live Science, the effect of "pearly clouds" is possible due to the refraction or scattering of sunlight from tiny ice crystals that form a rainbow effect. This phenomenon is possible only in the lower part of the stratosphere, at an altitude of 15 to 25 kilometers above the Earth's surface.

It is noted that this is a very rare phenomenon that became possible at a temperature of -121 degrees Fahrenheit or -85 degrees Celsius. According to Spaceweather.com, its appearance may be caused by climate change, which involves human activity.