What makes the northern lights dance

An international team has discovered when Earth's "magnetotail" snaps out in space, the northern lights start dancing across Canada's skies.

 
One explosive release in February -- which occurred about 127,000 kilometres away, or a third of the way to the moon -- sent enormous amounts of energy hurdling towards Earth. A minute-and-a-half later a spectacular aurora display lit up the skies, say the scientists, whose work with five NASA satellites and 20 ground stations across Canada and Alaska is revolutionizing our understanding of space weather.
 

"We discovered what makes the northern lights dance," lead investigator Vassilis Angelopoulos of the University of California, Los Angeles said in announcing the discovery Thursday.