While the Cassini spacecraft was orbiting Saturn, it spotted a star blinking out behind the planet's F ring. The star occultation indicated that a solid moonlet might be present, which was nicknamed "Mittens" by researchers. This artist's conception shows how "Mittens" (the object to the right of the star) may appear to Cassini.

Observing the flickering of starlight passing through Saturn's rings, researchers discovered 13 objects in the F ring ranging in size from 30 yards to six miles (27 meters to 10 kilometers) in length. Since most of the objects were translucent, with some starlight passing through them, the researchers concluded they probably are temporary clumps of icy boulders that are continually shattering and reforming.

Cat names like "Mittens" and "Fluffy" were chosen for these moonlets, because they appear to unexpectedly appear and disappear, and have multiple lives.

Cassini became the first spacecraft to explore the Saturn system of rings and moons from orbit, when it entered planetary orbit on Jun. 30, 2004. It immediately began sending back intriguing images and data. The European Space Agency's Huygens Probe plunged down into the dense atmosphere of Saturn's moon, Titan, in January 2005. Instruments on both spacecraft are providing vital data and the best views ever of this region of our solar system.

• Video Player: Cassini's Crossing
• VIDEO: Saturn Hexagon
• Cassini Special Report

— NASA/JPL/University of Colorado and SPACE.com Staff

Credit: NASA/JPL/University of Colorado