Thanks to data collected by ESA’s Cluster spacecraft and a NASA mission called the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE), scientists have solved a long-standing space mystery – the origin of a colorful display in the night sky known as the theta aurora. Theta aurora over Antarctica. This image obtained in 1983 shows the auroral oval and a transpolar arc; the arc extends into the polar cap from local midnight, across...
