GLANCING BLOW: Arctic sky watchers should be alert for Northern Lights on Nov. 5th. NOAA forecasters say there is a chance that a coronal mass ejection (CME) will hit Earth's magnetic field, and the impact could spark a high-latitude geomagnetic storm. The Solar and Heliospheric Observatory recorded this movie of the CME:
The billon-ton cloud was blown into space by departing sunspot 1029 on Oct. 31st. Normally, CMEs take only two or three days to reach Earth, but during the deep solar minimum of 2008-2009, the clouds have slowed to a veritable crawl (~350 km/s, down from 700 to 1000 km/s). Crossing the sun-Earth divide now requires about five days, so an Oct. 31st CME should arrive on Nov. 5th. Because the blast was not squarely Earth-directed, the sluggish CME will deliver at most a glancing blow. NOAA forecasters estimate a 5% chance of strong geomagnetic storms around Earth's poles.
