Phoebe

Phoebe is a Saturn moon whose path around Saturn runs opposite to that of most other moons.[1] JPL gives Phoebe a mean radius of 106.50 kilometres.[2] Phoebe's dark surface sends back only a small fraction of incoming sunlight.[1]

History

William Pickering identified Phoebe in August 1898.[1] Cassini's first targeted encounter after reaching Saturn was with Phoebe in 2004.[1]

Findings

NASA treats Phoebe's dark surface and unusual path as clues that Saturn may have captured it.[1] A possible explanation for Phoebe's origin is that it once belonged to the Centaur population.[1] NASA characterizes Centaurs as primitive bodies left over from the early solar system.[1] ESA gives Phoebe a diameter of 220 kilometres.[3]

Sources

  1. Phoebe | NASA Science. Licence: facts-only (Track B), no text or images reused. Attribution: NASA.
  2. Planetary Satellite Physical Parameters | NASA Jet Propulsion Laboratory. Licence: facts-only (Track B), no text reused. Attribution: NASA/JPL-Caltech.
  3. Saturn's moons | ESA. Licence: facts-only (Track B), no text reused. Attribution: European Space Agency.

Evidence as of 2026-11-01.