https://motherboard.vice.com/en_us/article/vb94ed/nasa-says-it-caused-otherworldly-lights-in-the-arctic-circle

NASA set the Arctic Circle ablaze last week with colorful blue vapor clouds that were seen above parts of Finland and Norway. And yes, they did cause some people to ask: Aliens?

The apparition was caused by a NASA rocket launch that discharged “gas tracers” into the sky to probe the mechanisms behind auroras. The Saturday mission, named “AZURE” for the Auroral Zone Upwelling Rocket Experiment, launched from Norway’s Andøya Space Center just after midnight local time, and after several attempts in 2018 were scuttled due to bad weather.