It's weird how radiation can provoke so much mayhem and fear and yet produce this inspiring, overwhelming beauty. I've watched many spectacular videos and images auroras, but this video by Norwegian photographer Terje Sorgjerd is the best so far.
Auroras are created by radiation coming from the sun and hitting Earth's magnetic field. As the solar wind hits the Earth's atmosphere, ionized nitrogen atoms regain and electron and oxygen and nitrogen atoms from excited to ground state. They produce photons during that process, with the oxygen emitting green or brownish-red and the nitrogen producing blue—gaining electrons—or red—going to ground state.
Personally, I've run out of excuses for not going to the Kirkenes and Pas National Park, in northern Norway, where this video was filmed at sub-zero temperatures. [TSO Photography—Thanks Karl!]