Surprise! Saturn has a Small Moon Hidden in Its Ring

"The moon's discovery and the disturbance of its trajectory by the neighboring moon Mimas highlight the close association between moons and rings that we see throughout the Saturn system," says Cassini imaging team scientist Carl Murray of Queen Mary University of London, in a statement.

The moon is about one-third of a mile (a half-kilometer) across and circles Saturn as a part of the planet's sixth, or G, ring.  "Before Cassini, the G ring was the only dusty ring that was not clearly associated with a known moon, which made it odd," said Matthew Hedman, a Cassini imaging team associate at Cornell University in Ithaca, New York. "The discovery of this moonlet, together with other Cassini data, should help us make sense of this previously mysterious ring."