S.C. Auroras appear as wispy, luminous bands or streamers of light, extending from 40 to 600 miles above Earth. They occur when solar gases blow across Earth's magnetic field and send charged particles into the upper atmosphere. Colo. The color depends on the type of atom or molecule struck by charged particles from the sun. Oxygen produces a brilliant, yellow-green aurora. Nitrogen can glow blue, red or purple, depending on its electrical state and the strength of the particle that hits it.
Auroras usually form after solar eruptions.
Such eruptions are predicted to be more frequent from January to April, when the sun is at the peak of its 11-year cycle. The light shows occur over Earth's polar regions, where the planet's magnetic lines of force plunge into the atmosphere at the north and south magnetic poles. Energetic particles from the sun follow the lines of force down into the atmosphere where they smash into oxygen and nitrogen molecules. Auroral displays vary from night to night, but usually a diffuse patch of glowing sky can be seen first, followed by an arc that brightens perhaps a thousand fold in a minute. Auroras are often short-lived because Earth's atmosphere can recover from even a big solar storm within a day.