A Norway Aurora from Oct. 10, 2012

Aurora that appears to be casting rays of green sunlight through the clouds.

A coronal mass ejection hit Earth's magnetic field on Oct. 8, 2012 sparking a dramatic display of Arctic lights that is only slowly subsiding three days later. Hugo Løhre photographed the auroras over Lekangsund, Norway, on Oct. 10, 2012.

More lights like these could appear on Oct. 14-15. That's when a stream of solar wind spewing from a hole in the suns atmosphere (a "coronal hole") is expected to reach Earth, possibly sparking geomagnetic storms when it arrives.

Text: Dr. Tony Phillips
Image courtesy of Hugo Løhre