Large Coronal Hole

HOLE IN THE SUN’S ATMOSPHERE: A vast hole has opened in the atmosphere over the sun’s south pole, and it is spewing solar wind into space. The gaseous gap, a.k.a. a ‘coronal hole,’ is colored dark-purple in this extreme ultraviolet image from NASA’s Solar Dynamics Observatory:

Curved lines trace the sun’s magnetic field in this EUV image from SDO

Coronal holes are places where the sun’s magnetic field opens up and allows solar wind to escape. A stream of solar wind flowing from this particular hole is expected to reach Earth’s orbit on Jan. 4-5. The bulk of the stream will flow south of our planet. However, not all of it will miss. NOAA forecasters estimate a 40% chance of polar geomagnetic storms when the solar wind arrives in the next 48 hours.