When I lived in Glendive, Montana we could see what we called the Northern Lights and they moved back and forth like a light show. This picture was taken in Alaska but what we saw was similar, though perhaps fainter. I just read that scientists think they have discovered the energy source. New data from NASA's Themis mission (satellites lauched this winter) found the energy comes from a stream of charged particles from the sun flowing like a current through twisted bundles of magnetic fields connecting eath's upper atmosphere to the sun.
They said there was a two hour light show in March over Alaska and Canada and the geomagnetic storm raced 400 miles in a minute across the sky (equal to a 5.5 earthquake).
I was surprised to read they had expected the existence of these wound-up bundles of magnetic fields but this is the first time it was ever mapped--and get this--mapped some 40,000 miles above the Earth.
It is an amazing world we live in and so much we still don't know about it.