This movie from the SOlar and Heliospheric Observatory (SOHO) shows the sun's atmosphere – the corona – from September 17 to September 20. Numerous CMEs blasted off the sun during this period. Credit: ESA/NASA/SOHO › Play/Download video › Download still
The sun let loose with at least six coronal mass ejections (CMEs) -- solar phenomena that can send solar particles into space and affect electronic systems in satellites -- from 7 PM ET on September 18, 2011 until 1 PM on September 19. The ejections appear to come from points scattered over the surface of the sun. Two CME's dissipated quickly, but four continue to spread outward from the sun. NASA models suggest that the leading edge of one CME will pass by Earth at around 5 PM ET on Sep 21, at which point sky watchers should be on the lookout for auroras.