AMAZING STRATOSPHERIC CLOUDS OVER EUROPE: When the sun set over the UK on Dec. 9th, sky watchers were stunned by an unexpected apparition of super-colorful stratospheric clouds.
Above photographs, my friend Lesley.
"These are nacreous clouds," explains atmospheric optics expert Les Cowley. "Of all Earth's clouds they are most spectacular, and a very rare treat for skywatchers."
"For up to an hour after sunset or before dawn they glow like eerie electric discharges or gas jets in the darkening sky, their filmy shapes slowly curling and uncurling with intense shifting colors. They are composed of tiny ice crystals more than twice as high as ordinary clouds, 9-16 miles up, in the stratosphere and form at temperatures of minus 85 Celsius and below. The crystals are all of similar size and they diffract the high altitude sunlight to make the colours."
Explanation Courtesy of Spaceweather.com.
So there you go.