Often, great displays of the Northern Lights (aurora borealis) do insane things. Several times, over many years, they seemed to hover directly over me, personally. They swirled wildly overhead, as if they knew where I was standing. Looking straight up, I saw:
I never understood how this could be … until one night, standing under a great display, puzzling very hard over the problem, it hit me. It felt like a Nobel-Prize-worthy discovery. ah-HA!
Imagine you’re lying on your back on the floor in somebody’s living room, looking up at a set of lace curtains. The curtains to either side of you will fall down in straight lines to your left and right. But directly above you, you’ll see a complex, maybe S-shaped curve, surrounded by lines radiating from a point above your head. If you move to another spot along the curtains, you’ll see the same thing, due to perspective.
NASA photos taken looking down from Earth orbit aboard one of the Space Shuttles confirm that this is pretty much what’s actually happening:
