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.