August 28, 2010
Your birthday marks the moment a small planet circling a modest star gained another witness to its wonders.
Hole in the Sun
Birthday · August 28, 2010
A little universe, just for you
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APOD published August 28, 2010. Full image credits are on the original APOD entry below. A publication-date match, not a photo taken on your date. Independent of NASA.
This ominous, dark shape sprawling across the face of the Sun is a coronal hole -- a low density region extending above the surface where the solar magnetic field opens freely into interplanetary space. Studied extensively from space since the 1960s in ultraviolet and x-ray light, coronal holes are known to be the source of the high-speed solar wind, atoms and electrons which flow outward along the open magnetic field lines. During periods of low activity, coronal holes typically cover regions just above the Sun's poles. But this extensive coronal hole dominated the Sun's northern hemisphere earlier this week, captured here in extreme ultraviolet light by cameras onboard the Solar Dynamics Observatory. The solar wind streaming from this coronal hole triggered auroral displays on planet Earth.