Aurora
Aurora (phenomenon), luminous atmospheric phenomenon occurring most frequently above 60° North or South latitude, but also in other parts of the world. It is named specifically, according to its location, aurora borealis (northern lights) or aurora australis (southern lights). The term aurora polaris, polar lights, is a general name for both. The aurora consists of rapidly shifting patches and dancing columns of light of various hues. Extensive auroral displays are accompanied by disturbances in terrestrial magnetism and interference with radio, telephone, and telegraph transmission. The period of maximum and minimum intensity of normal auroras seems to be almost exactly opposite that of the sunspot cycle, which is an 11-year cycle, so the intensity of the auroras is normally low while the sun is very active. Huge displays that occur farther from the earth’s poles than normal, however, occur more often while the sun is very active.