A coronal mass ejection (CME) hit Earth on Oct. 24th at approximately 1800 UT (2:00 pm EDT). The impact strongly compressed Earth's magnetic field, directly exposing geosynchronous satellites to solar wind plasma, and sparked an intense geomagnetic storm. As night fell over North America, auroras spilled across the Canadian border into the contiguous United States. A US Department of Defense satellite photographed the crossing:

"This shows the auroras on Oct. 25th at 0140 GMT," says Paul McCrone of the Fleet Numerical Meteorology and Oceanography Center in Monterey, California. He created the image using visual and infrared data from the Defense Meteorological Satellite Program's F18 polar orbiter. DMSP satellites carry low light cameras for nightime monitoring of moonlit clouds, city lights and auroras. Some of the auroras recorded by the F18 on Oct. 25th were as bright as the city lights underneath.