Friday, August 20, 2010


August 20. 2010
A coronal hole on the sun is turning to face Earth. Coronal holes are places in the sun's atmosphere where the magnetic field opens up and allows solar wind to escape. Here is a magnetic map of the hole from NASA's Solar Dynamics Observatory:
Image credit: Karel Schrijver, Lockheed Martin SAL
In the image, magnetic field lines are color-coded. White field lines are closed; they hold the solar wind in. Golden field lines are open; they allow the solar wind out.
A stream of solar wind flowing from this coronal hole is expected to reach Earth on or about August 24th. High-latitude sky watchers should
be alert for auroras when it arrives.

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