IUVS observations of a proton aurora

MAVEN observations of a proton aurora. In the top panel, natural variability of the solar wind results in occasional dense flows of solar wind protons bombarding Mars. At bottom, observations by MAVEN’s Imaging Ultraviolet Spectrograph show increased ultraviolet emission from the atmosphere when the solar wind is enhanced. (Courtesy NASA/MAVEN/University of Colorado/LASP/Anil Rao)