Video Caption: A very long solar filament that had been snaking around the Sun erupted Dec. 6, 2010 with a flourish. NASA’s Solar Dynamics Observatory (SDO) caught the action in dramatic detail in extreme ultraviolet light of Helium. It had been almost a million km long ((about half a solar radius) and a prominent feature on the Sun visible over two weeks ago before it rotated out of view. Filaments are elongated clouds of cooler gases suspended above the Sun by magnetic forces. They are rather unstable and often break away from the Sun.
[image-69][image-96]UPDATE: The "mega-filament" described below has just erupted. NASA's Solar Dynamics Observatory made a must-see movie (above) of the epic blast. The eruption does not appear to be headed toward Earth.
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 the above picture during the early hours of Dec 6, 2010.
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. Further updates will be posted as warranted.