Cassini finds moon hidden in Saturn's rings

Last week NASA announced that the Cassini space probe has found a 4-mile wide moon hidden in the Keeler gap of Saturn's rings that leaves a trail of gravitational ripples in its wake. Provisionally named S/2005 S1, it is the second such moon found to exist within Saturn's rings (after the 16-mile long Pan, located in the Encke gap). On top of 12 other new moons confirmed two weeks ago, there are now 47 known moons orbiting Saturn - though several, like Phoebe, are now believed to be captured satellites that originated in the Kuiper Belt region of the outer solar system.