NASA's MAVEN mission has returned images showing the ultraviolet glow from the Martian atmosphere in unprecedented detail, revealing dynamic, previously invisible behaviour.They include the first images of "nightglow" that can be used to show how winds circulate at high altitudes, NASA said in a statement on Tuesday. Nightglow is a common planetary phenomenon in which the sky faintly glows even in the complete absence of external light Scientists predicted nitric oxide (NO) nightglow at Mars, and prior missions detected its presence, but MAVEN has returned the first images of this phenomenon in the Martian atmosphere, the statement added.Additionally, dayside ultraviolet imagery from the spacecraft shows how ozone amounts change over the seasons and how afternoon clouds form over giant Martian volcanoes. "MAVEN obtained hundreds of such images in recent months, giving some of the best high-resolution ultraviolet coverage of Mars ever obtained," said Nick Schneider of the Laboratory for Atmospheric and Space Physics at the University of Colorado, Boulder.The images were taken by the Imaging UltraViolet Spectrograph (IUVS) on MAVEN.Schneider will present these results on October 19 at the American Astronomical Society Division for Planetary Sciences meeting in Pasadena, California, which is being held jointly with the European Planetary Science Congress.The Mars Atmosphere and Volatile Evolution (MAVEN) mission was launched in November 2013 to explore the Red Planet's upper atmosphere, ionosphere and interactions with the sun and solar wind.