NASA's Cassini spacecraft has detected a thin layer of oxygen
around Dione, one of Saturn's icy moons. Although Dione's oxygen
layer is too thin to qualify as an "atmosphere," the discovery
lends support to a theory that all of the moons orbiting our
solar system's gas giants may actually have oxygen around them.
Scientists believe the oxygen surrounding the moons of Jupiter
and Saturn may be generated when the planets' powerful radiation
belts split cause the moons' ice to break apart into its
hydrogen and oxygen components. That means that even though
Dione can't support life -- due to a lack of liquid water --
it's possible that another moon could. "Some of the other moons
have liquid oceans and so it is worth looking more closely at
them for signs of life," said Professor Andrew Coates of
University College London, one of the authors of a paper on the
discovery.