CORONAL HOLE: Spewing solar wind, a yawning dark fissure in the sun’s atmosphere is turning toward Earth. NASA’s Solar Dynamics Observatory photographed the “coronal hole” during the early hours of June 1st:

Coronal holes are places where the sun’s magnetic field opens up and allows the solar wind to escape. A stream of solar wind flowing from this coronal hole will reach Earth on June 5th – 7th, possibly stirring geomagnetic storms. High-latitude sky watchers should be alert for auroras

from:    space weather.com