"This is how the sky looked 11 hours after the CME impact," says Yoneto, who used a Canon EOS 6D digital camera to record the reds.
Auroras are usually green, and sometimes purple, but seldom do sky watchers see this much red. Red auroras occur some 300 to 500 km above Earth's surface and are not yet fully understood. Some researchers believe the red lights are linked to a large influx of electrons. When low-energy electrons recombine with oxygen ions in the upper atmosphere, red photons are emitted. At present, space weather forecasters cannot predict when this will occur.
During the storm, even more red auroras were observed over the United States in places like Kansas, Ohio, and Oklahoma. Browse the gallery for examples. - Space Weather.