Scientists think they have discovered the energy source of auroras borealis, the spectacular color displays seen in the upper latitudes of the Northern Hemisphere.
New data from NASA's Themis mission, a quintet of satellites launched this winter, found the energy comes from a stream of charged particles from the sun flowing like a current through twisted bundles of magnetic fields connecting Earth's upper atmosphere to the sun.
The energy is then abruptly released in the form of a shimmering display of lights, said principal investigator Vassilis Angelopoulos of the University of California at Los Angeles.
Results were presented Tuesday at the American Geophysical Union meeting.
