IRIS Movie of the Day
At least once a week a movie of the Sun taken by NASA's Interface Region Imaging Spectrograph (IRIS) is posted by one of the scientists operating the instrument.
Coronal Mass Ejection caught in the act
Credit: IRIS, LMSAL/NASA, Bart De Pontieu
Coronal mass ejections (CME) are eruptions in the solar atmosphere in which plasma is expelled into the solar wind. IRIS caught this nice CME during a period when the Sun is not particularly active. Even during solar minimum conditions, the Sun continues to produces CMEs on a roughly daily basis. This CME appears to occur in two stages with an initial filament eruption involving apparently unwinding/twisting motions followed by a very fast eruption associated with a small two-ribbon flare. The CME eruption is nicely caught under the slit, as well as the pre- and post-CME state of the atmosphere. Data such as this are invaluable to better understand why and how these eruptions occur.