Phobos

Phobos is a Martian moon orbiting very close to the planet, one of two that Mars has.[1] JPL puts the mean radius of Phobos at 11.08 kilometres.[2]

History

Asaph Hall discovered Phobos in 1877.[1]

Findings

Its orbit is gradually shrinking, bringing the moon closer to Mars.[1] USGS lists craters, dorsa, planitiae, and regiones among mapped feature types on Phobos.[3]

Sources

  1. Phobos | NASA Science. Licence: facts-only (Track B), no text or images reused. Attribution: NASA.
  2. Physical Parameters | NASA/JPL. Licence: facts-only (Track B), no text reused. Attribution: NASA/JPL-Caltech.
  3. Gazetteer of Planetary Nomenclature | USGS. Licence: US federal work, public domain (17 USC 105). Attribution: U.S. Geological Survey.

Evidence as of 2026-11-01.