A HOLE IN THE SUN’S ATMOSPHERE: An irregular hole in the sun’s atmosphere is turning to face Earth, spewing a ragged stream of solar wind toward our planet. Estimated time of arrival: Oct. 23-24. NASA’s Solar Dynamics Observatory took this false-color UV image of the structure on Oct. 20th:
This is a “coronal hole”–a place where the sun’s magnetic field opens up and allows solar wind to escape. Coronal holes look dark because the glowing-hot plasma normally contained there is missing. In this case, it is en route to Earth.
High-latitude sky watchers should be alert for auroras when the gaseous material arrives. A bright full Moon on Oct. 24th will add its luminosity to that of any geomagnetic storm, creating some nice landscape photo-ops around the Arctic Circle.Free: Aurora Alerts.