The shifting, shimmering Northern Lights might be more ordered than
anyone realised. New observations suggest that, contrary to
expectations, some of the colourful light shows appear to be
polarised, with their electromagnetic waves lined up in a common
orientation.

If confirmed, the discovery will provide a powerful new tool to
understand the Earth's magnetic field and the atmospheres of other
planets.

More at http://space.newscientist.com/article/dn13802-is-there-a-hidden-order-to-the-northern-lights.html