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.
Repeating Eruption Summons Potential
Credit: IRIS, LMSAL/NASA, Jakub Prchlik
Dynamic solar events are rarely detectable in visible light, which probes the sun at roughly 6000K (~10,000 degrees F). Therefore, space telescopes like IRIS observe the sun in the ultraviolet, which measures the sun at roughly 65,000K (~120,000 degrees F). While pointing at the Sun's eastern limb, IRIS observes a repeating eruption. The eruption emerges near the solar surface where one sees a brightening arch. The brightening arch coincides with an expulsion of material roughly seven times. Each expulsion ejects material roughly 10 earth radii from the solar surface. During the first seven expulsions, material condenses and precipitates back to the solar surface (aptly named coronal rain). Finally, the eighth and most energetic expulsion ends the repeating eruption and corresponding coronal rain.