July 23th CME...From Long-Gone AR 1520

The above image was taken July 23rd by the Solar Dynamics Observatory. The image captures the coronal mass ejection (CME) which erupted (at lower right) from Active Region 1520, beyond the sun's western limb. Image Credit NASA/SDO/AIA

On July 23rd Active Region 1520 (AR 1520) made more noise from well beyond the western limb of the sun. At 03:00 UTC (11:00 PM EDT July 22nd), the Solar and Heliospheric Observatory (SOHO) recorded the emergence of a solar flare from behind the limb. The AR 1520 issued a solar flare and coronal mass ejection (CME). The CME speed was rated at 2,930 km/s, or 6.5 million mph. CMEs which move this fast occur only once every 5 to 10 years.  And even though the eruption was at such an oblique angle relative to Earth, it resulted in a minor (S1) solar radiation storm at Earth. The GOES spacecraft began registering an increase in protons around 07:30 UTC (3:30 AM EDT). Forecasters expect the storm to stay at minor levels and slowly wane over the next 12 to 24 hours.

Forecasters were very grateful of the fact that this CME was not directed toward Earth. They also report that the CME will miss all of the inner planets.

To monitor solar flare activity minute by minute, visit the "Today's Space Weather" page of NOAA's Space Weather Prediction Center, URL: www.swpc.noaa.gov .

To learn more about the sun and to stay current on solar activity, visit the mission home pages of the Solar Dynamics Observatory (SDO), sdo.gsfc.nasa.gov and the Solar and Heliospheric Observatory (SOHO), sohowww.nascom.nasa.gov .

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