The Sun was visually dominated by three substantial coronal holes that rotated across the face of the Sun this week (Sept. 8-10, 2015). Coronal holes are areas where the Sun's magnetic field is open and a source of streaming solar wind. They appear darker in extreme ultraviolet light because there is less material in the hole areas being imaged in this specific wavelength of light. It is a little unusual to have three coronal holes at the same time, but neither is it a rare occurrence.

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PIA19950_Coronal_holes_AIA211_big.mp4
PIA19950_Coronal_holes_AIA211_sm.mp4

SDO is managed by NASA's Goddard Space Flight Center, Greenbelt, Maryland, for NASA's Science Mission Directorate, Washington. Its Atmosphere Imaging Assembly was built by the Lockheed Martin Solar Astrophysics Laboratory (LMSAL), Palo Alto, California.