Not a UFO

I don't know what it is. No one does, yet. I'm sure it's not a UFO - well, actually, it technically is an Unidentified Flying Object, I suppose, but not of the Li'l Green Man variety. 

This strange spiral in the sky appeared in Norway and has a ton of documentation. I'll be interested to hear if they ever determine what it is. My bet: Weather Balloons. Green (AHHHHHHHH!)