MAVEN obtained this ultraviolet image of hydrogen surrounding comet C/2013 A1 (Siding Spring) on October 17, 2014, two days before the comet’s closest approach to Mars. The IUVS instrument imaged the comet at a distance of 5.3 million miles (8.5 million kilometers). The image shows sunlight that has been scattered by atomic hydrogen, and is shown as blue in this false-color representation.
