AR 3664: Giant Sunspot Group

Explanation: Right now, one of the largest sunspot groups in recent history is crossing the Sun. Active Region 3664 is not only big -- it's violent, throwing off clouds of particles into the Solar System . Some of these CME s are already impacting the Earth, and others might follow. At the extreme, these solar storms could cause some Earth-orbiting satellites to malfunction , the Earth's atmosphere to slightly distort, and electrical power grids to surge . When impacting Earth's upper atmosphere , these particles can produce beautiful auroras, with some auroras already being reported unusually far south . Pictured here, AR3664 and its dark sunspot s were captured yesterday in visible light from Rome , Italy . The AR3664 sunspot group is so large that it is visible just with glasses designed to view last month's total solar eclipse . This weekend, skygazing enthusiasts will be keenly watching the night skies all over the globe for bright and unusual auroras .

Gallery: Active Region 3664 on the Sun and Associated Aurora