Aurora in Red and Yellow . ... Credit Copyright: Jan Safar ( Brno Observatory ) Explanation: The past week brought some spectacular aurora to northern skies. These aurorae were caused by a large interplanetary shock wave that exploded from the Sun on April 4 . When the shock wave reached the Earth on April 6, the resulting aurora could be seen in clear skies as far south as North Carolina . ... NASA Web Site Statements, Warnings, and Disclaimers . NASA Official: Jay Norris. ...