Is Phoebe a natural child of Saturn, or a foundling? Phoebe is a small moon, just over 200 kilometers across, made of more stone and less ice than Saturn’s inner moons, adding credence to the suggestion that it is not quite part of the family, but something of an outsider. One possibility is that it is a captured Centaur, an ice-rock that once wandered more freely through the realms of the gas giants until falling into Saturn’s gravitational grasp. If so, then it is the only such object that has been imaged in anything like the detail seen here.
© Springer Science+Business Media, LLC 2008