page_title: Phobos (moon)
hierarchical_section_title: Phobos (moon)
caption_attribution_description: English: A simulated view of the orbits of Phobos and Deimos.
context_page_description: Phobos is one of Mars' moons. The other is Deimos.
  Phobos is the larger of the two moons, and is only 27 kilometers in diameter. This is about as far as a car can travel on the highway in 15 minutes. It is covered with craters, as Earth's moon is.
  It is named after the god Phobos in Greek mythology. Its name means "fear".
  Phobos is trapped in tidal drag, with its orbit lowering roughly 1.8 meters per century. In about 50 million years, Phobos will reach the Roche limit, where it is likely to be torn apart. Some fragments will fall on Mars and some will form a planetary ring or rings around Mars.
  The other moon, Deimos, is the smaller of the two.
context_section_description: Phobos (or Mars I) is one of Mars' moons. The other is Deimos.
  Phobos is the larger of the two moons, and is only 27 kilometers in diameter. This is about as far as a car can travel on the highway in 15 minutes. It is covered with craters, as Earth's moon is.
  It is named after the god Phobos in Greek mythology. Its name means "fear".
  Phobos is trapped in tidal drag, with its orbit lowering roughly 1.8 meters per century. In about 50 million years, Phobos will reach the Roche limit, where it is likely to be torn apart. Some fragments will fall on Mars and some will form a planetary ring or rings around Mars.
  The other moon, Deimos, is the smaller of the two.
caption: Orbits of Phobos and Deimos (to scale), as seen from above Mars