COLORFUL 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.
[link to www.spaceweather.com]

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