If you were watching the news yesterday, you probably came across this story.
Don't worry, it's not aliens. It's not a giant laser light show. It's not someone trying to hypnotize part of the northern hemisphere. The Bad Astronomy blog has a good write up on this (and the comments are equally interesting). Specifically, there was a Russian launch postponed until approximately that time and there was a NavTEX warning message prohibiting travel in the White Sea due to a rocket launch. Oh, and there's some confirmation that it was, indeed, a Russian Bulava test firing.
It still looks amazing.