Admit it – you always wondered what caused Northern Lights (Aurora Borealis. Now NASA has nailed it down – it mainly revolves around magnetic fields getting stretched and then snapping. That was always my theory, but now it is definite. (!)

Here is how NASA describes it:

The key to the auroras is magnetic reconnection, which NASA describes as “stressed magnetic field lines that suddenly snap to a new shape, like a rubber band that’s been stretched too far,” causing a burst of light and movement near the northern and southern poles. “We discovered what makes the Northern Lights dance,” said UCLA’s Vassilis Angelopoulos, who is the principal investigator for the THEMIS mission.

OK, it’s all a bit geeky, but this is a tech blog, after all. And we love Astronomy around here.

CNet has a good story on the issue with some great photos – see it here