NASA SDO Image: Solar Magnetic Filament

A magnetic filament snaking around the sun's SE limb just keeps getting longer.

The portion visible today stretches more than 700,000 km--a full solar radius. NASA's Solar Dynamics Observatory took this picture during the early hours of Dec. 6th:

NASA's STEREO-B spacecraft, stationed over the sun's eastern horizon, saw this filament coming last week. 

So far the massive structure has hovered quietly above the stellar surface, but now it is showing signs of instability. 

Long filaments like this one have been known to collapse with explosive results when they hit the stellar surface below. Stay tuned for action.

More images: from Robert Arnold of Isle of Skye, Scotland; from Cai-Uso Wohler of Bispingen, Germany; from Gianfranco Meregalli of Milano, Italy; from Francisco A. Rodriguez of Cabreja Mountain Observatory, Canary Islands; from Larry Alvarez of Flower Mound, Texas;