The Aurora Borealis, better know as the Northern Lights, is a phenomenon caused by the collision of charged particles (electrons, protons and some heavier particles) from the Earth’s magnetosphere with atoms and molecules in the upper atmosphere induced by solar wind. This provides energy to the molecules causing a temporarily excited state which is then lost as light emission (mostly green, red and high blue/violet). This light emission creates one of the most beautiful natural phenomena known to man and can been seen flickering across the sky. Unfortunately unless you live or travel near to the North Pole, you’re very unlikely to see it yourself. Along those lines here is a fantastic animation of the Aurora Borealis from space first posted by the NY Times:

Hit the read link for another beautiful video.

This next video is a very nice time lapse shot of the Northern lights and shows you what it would look like if you happened to travel up to Northern Canada or Lapland.