Sparkling polar stratospheric clouds appeared over the Norwegian city of Tromsø on December 16th - a phenomenon that can be transient, but very beautiful.
As the regions of the Arctic sink into darkness this winter, the sky will be colored with some beautiful natural phenomena. The activity of near-polar phenomena is expected as the particles of the solar wind fly through the atmosphere, but sometimes more rare phenomena appear.
On these stunning photos, strange luminous objects formed over the northern Norwegian city of Tromsø on December 16th, to the great joy of photographer Truls Tiller.
“The sun has already disappeared,” Tiller told SpaceWeather.com, “but this beautiful view makes winter darkness much nicer. The picture was taken at 10.30 am, in the middle of the “day”.
These clouds, called polar stratospheric clouds (or PSCs), form in the stratosphere at about 15 miles altitude. The “ordinary” gray-white clouds, which are more familiar to us, are located in the troposphere below, between 3 and 6 miles of altitude.
Since PSCs are at such a high altitude, they consist of ice in a layer where temperatures can drop to -85 degrees Celsius (-121 Fahrenheit). Then, if the angle of the sun is straight (below the horizon), an amazing light show can begin in the sky. And the twilight skies over Tromsø turned out to be ideal for such a “view”.
It is not surprising that such clouds are also called pearlescent, because tiny ice particles (only ~ 10 µm in diameter) strongly refract light, causing the appearance of unusually bright colors that eclipse the usual rainbow clouds that are found all over the world. Although these unusual phenomena are beautiful, according to SpaceWeather.com, such clouds are associated with the destruction of the ozone layer and the appearance of ozone holes at high altitude.
