irregular moon · moon of Saturn
Phoebe
A dark, distant moon of Saturn on a backwards orbit, probably a captured body from the outer Solar System.
- Distance from Earth today
- 1.28 billion km8.564 AU · light: 1 h 11 min
- Distance from the Sun today
- 1.41 billion km9.425 AU
- As of
- 3 November 2026position from NASA/JPL orbital elements
Where it is today
Top view of the plane of Earth’s orbit, compressed distance scale. Open on the big map with the time slider →
Facts
- Diameter
- 213 km
- Mass
- 8.31 × 10¹⁸ kg
- Density
- 1,643 kg/m³
- Mean distance from the planet
- 12,929,400 km
- Orbital period
- 1.51 years
- Orbital eccentricity
- 0.164
- Orbital inclination
- 175.2°
Source of the figures: JPL SSD – Planetary Satellites (public domain).
Discovery: 1898 – William Henry Pickering
Description
Phoebe was discovered in 1898 by William Henry Pickering, the first moon found on photographic plates. It orbits Saturn far beyond the major moons and in the retrograde direction, a strong sign that it was captured rather than formed in place, perhaps from the population of icy bodies beyond Neptune. Cassini flew close to Phoebe in 2004, shortly before reaching Saturn, and found a dark, heavily cratered surface hiding ice beneath. Dust knocked off Phoebe forms an enormous, faint ring around Saturn that was discovered by the Spitzer Space Telescope.