VIDEO DESCRIPTION FROM SOHO: In an event reminiscent of some of the Discovery Channel Mythbusters' most spectacular explosions, the Sun on June 7, 2011, starting at about 06:41 UT unleashed one of the most spectacular prominence eruptions ever observed, in fact, one could call it a "prominence explosion". But this explosion was larger by far than any rigged by Mythbusters: the prominence material expanded to a volume some 75 times as big across as the earth!
SDO's Atmospheric Imaging Assembly recorded the amazing event in stunning detail, and SOHO's LASCO coronagraph and STEREO's SECCHI instrument suite observed the prominence and associated CME as they traveled out into the heliosphere. Using LASCO and SECCHI data, the speed of the leading edge of the CME was estimated to be in the range 1200 - 1600 km/s. Model calculations predict that Earth will receive a glancing blow of the CME on June 10, possibly sparking some nice aurorae at high latitudes.
The event originated from the almost spotless active region 11226 and was associated with a moderate M2-class X-ray flare. The CME and associated shock wave produced and S1-class radiation storm, which shows up as speckles in the LASCO movies.
This event is not only one of the most spectacular ever recorded, but also one of the best observed, with complementary data from several spacecraft and different vantage points (SDO, SOHO, STEREO).