8.01.2024

On Jan. 5th, two seemingly unrelated things happened in Stockholm, Sweden: A punishing cold wave hit the city, plunging the air temperature almost 30 degrees below freezing. At the same time, aurora-colored lights filled the sky. Yet these were not auroras:

"With the extreme cold, ice crystals filled the air," says photographer Peter Rosén in downtown Stockholm. "This created a magnificent display of light pillars that looked almost like Northern Lights."

Light pillars are manmade lights spread into colorful columns by large wobbly snowflakes and other crystals. No solar activity is required. The only ingredients are ice and light pollution.

The red lights in Rosén's photo are aircraft warning beacons on tall buildings and construction cranes. Other colors correspond to high pressure sodium lamps (warm orange) and modern LED lamps (blue-white).

Quelle: SpaceWeather