Loading video... VIDEO: The famed northern and southern lights have been studied for millennia, but they still hold secrets. In a new study, physicists led by the University of Iowa describe a new... view more Credit: Riley Troyer, University of Iowa For millennia, humans in the high latitudes have been enthralled by auroras--the northern and southern lights. Yet even after all that time, it appears the ethereal, dancing ribbons of light above Earth still hold some secrets. In a new study, physicists led by the University of Iowa report a new feature to Earth's atmospheric light show. Examining video taken nearly two decades ago, the researchers describe multiple instances where a section of the diffuse aurora--the faint, background-like glow accompanying the more vivid light commonly associated with auroras--goes dark, as if scrubbed by a giant blotter. Then, after a short period of time, the blacked-out section suddenly reappears.