Thin air: Cassini finds ethereal atmosphere around Saturn's ice moon Rhea
Sunday, November 28, 2010 - 23:31
in Astronomy & Space
NASA's Cassini spacecraft has detected a very tenuous atmosphere known as an exosphere, infused with oxygen and carbon dioxide around Saturn's icy moon Rhea. This is the first time a spacecraft has directly captured molecules of an oxygen atmosphere -- albeit a very thin one -- at a world other than Earth.