CORONAL HOLE: A hole in the sun’s atmosphere–a “coronal hole”–has opened up and it is spewing solar wind into space. NASA’s Solar Dynamics Observatory photographed the UV-dark gap during the early hours of May 29th:

Coronal holes are places where the sun’s magnetic field spreads apart and allows solar wind to escape. A windy stream of plasma flowing from this particular hole should reach Earth on June 2-3. The impact could spark geomagnetic storms and auroras around the poles

fr/spaceweather.com