TV engineer Stan Richard took this photo of the northern lights from Saylorville Lake, near Des Moines, Iowa. While the colorful rays seem to end just above the water, they are actually at altitudes of 60 miles (100 km) or higher.
The sun produced a second surface explosion within a week, sending another blast of radiation into Earth's atmosphere a few minutes later.
The following geomagnetic storm caused vivid displays of the northern lights as far south as Iowa, while the southern lights were seen as far north as Sydney, Australia.
The solar storm interfered with communications on Earth, and one burst of energy caused a complete blackout of GPS navigation satellite systems for two hours.
"It is a rare occurrence to have a strong event like this so late in the solar cycle," said Larry Combs, a forecaster at NOAA's Space Environment Center in Boulder, Colo.
The sun produces an 11-year cycle of sunspot activity, with the last peak occurring in 2002.
Photo: Stan Richard - NASA Photo of the Day