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.
Credit: IRIS, LMSAL/NASA, Charles Kankelborg (Montana State University)
The solar magnetic field is rent open as plasma erupts upward. The magnetic field then spontaneously "heals" in a process called reconnection, which sends heat and energetic particles downward. The resulting pair of bright ribbons on the solar "surface" are the iconic calling card of a solar flare. This "B-class" event is a thousand times fainter than the brightest class of solar flares, but it reached temperatures in excess of ten million degrees, and was a bright enough source of x-rays to briefly outshine the rest of the Sun in that band.