After about ten minutes of staring awe-struck out of the pitch black cockpit, I skipped through the cabin looking for people who were awake, telling them all, "LOOK OUT THE LEFT SIDE! NORTHERN LIGHTS!" and turning off all the lights in the galleys to encourage people to look. They just moved their headphones and looked at me and went, "Northern lights? Hm, you don't say," and went back to watching The Devil Wears Prada or whatever. But I was excited about it.
I didn't take these pictures - I just picked ones from a Google image search that looked the most like what I saw. The spiraling shape will make you go insane!