The detection of oxygen in the atmospheres of Jupiter's icy moons, Europa and Ganymede, and the presence of this gas as the main constituent of the atmosphere that surrounds Saturn's rings, has suggested the possibility of oxygen atmospheres around the icy moons that orbit inside Saturn's magnetosphere. Using the lon Neutral Mass Spectrometer onboard the Cassini spacecraft, Teolis et al. (p. 1813, published online 25 November; see the Perspective by Cruikshank) report the detection of a very tenuous oxygen and carbon dioxide atmosphere around Saturn's icy moon Rhea.
展开▼