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.
Sprucing Up the Place
Credit: IRIS, LMSAL/NASA, Chad Madsen, SAO
It appears the Sun has been doing some landscaping, with its latest addition being a freshly planted pine tree jutting out of its southeast limb. This arboreal protrusion is actually a solar prominence. These structures are comprised of cooler material close to the solar surface suspended high into the much hotter corona. Magnetic fields on the Sun are responsible for dredging up the cool material and pulling it outward to form these structures into a variety of brilliant shapes. This video features several observations of the same prominence taken intermittently over the course of about 14 hours. The prominence is far from static, showing gradual large-scale evolution over the course of hours in its overall shape as well as small-scale dynamical change over the course of minutes in the form of swirling streams of material. Its presence on the Sun may be short lived as prominences tend to be unstable, rendering them liable to suddenly and violently tear away from the Sun. As a final note, the periodic fuzziness seen in the video arises from energetic particles striking the IRIS detector. This usually happens once per orbit when the IRIS spacecraft briefly crosses a structure known as the Van Allen radiation belt which is comprised of energetic particles from the Sun trapped in Earth's magnetic field.