A large, dark coronal hole at the bottom of the Sun has been the most dominant feature this week (Jan. 29, 2014). Coronal hole are areas where the Sun's magnetic field is open ended and where high-speed solar wind streams into space. The area appears darker there because there is less material being imaged in this combination of threes wavelength of extreme ultraviolet. At its widest point, the hole extends about half way across of the Sun, close to 50 times the size of Earth.
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.