On October 26, NASA’s Solar Dynamics Observatory (SDO) caught the Sun “smiling.” Seen in ultraviolet light, these dark patches on the Sun are known as coronal holes and are regions where fast solar wind gushes out into space. SDO has studied how the Sun creates solar activity and drives space weather since its launch in 2010. Its observations begin in the interior of the Sun with the solar dynamo — the churning of the Sun’s interior that creates its magnetic field and drives space weather. Further out, SDO observes the solar surface to directly measure the magnetic field and the solar atmosphere. Finally, SDO measures the extreme ultraviolet irradiance of the Sun which is a key driver of the structure and composition of the Earth’s upper atmosphere.
