A Picture of the Moon Phobos

Phobos Moon Facts

  • Moon Name: Phobos
  • Other Names:: Mars I
  • Formed: Over 4 billion years ago
  • Discovered: August 18th, 1877 by Asaph Hall III
  • Distance from Mars: Between 5,738 miles (perigee) and 5,913 miles (apogee)
  • Time to Orbit Around Mars: About 0.318 Earth days
  • Total Surface Area: 962 square miles

18 Phobos Facts for Kids

  1. Phobos is one of the two natural satellites (moons) of the planet Mars.
  2. The name Phobos comes from Greek mythology. Deimos was the god of fear, the twin brother of Deimos and the son of Ares and Aphrodite.
  3. Phobos was discovered by Asaph Hall, III on August 18th, 1877.
  4. Phobos has very little mass, preventing it from forming a rounded shape with its own gravity.
  5. Phobos doesn’t have an atmosphere due to its low gravity and mass.
  6. Phobos has such little gravity that a person weighting 150 pounds on Earth would only weight two ounces on Phobos.
  7. Phobos has a surface area of about 962 square miles.
  8. The mean radius of Phobos is 7 miles.
  9. Phobos is the largest of the two moons that orbit Mars.
  10. The closest (perigee) Phobos’s orbit gets to Mars is 5,738 miles.
  11. The farthest (apogee) Phobos’s orbit gets from Mars is 5,913 miles.
  12. Phobos has the closest orbit of the two moons that orbit Mars.
  13. Phobos takes around seven Earth hours to orbit the planet Mars.
  14. Phobos is the closest orbiting moon to a planet in our Solar System.
  15. Phobos has little reflectivity and is one of the least reflective objects in our Solar System.
  16. Mariner 7 was the first spacecraft to photograph Phobos in 1969.
  17. The largest crater on the surface of Phobos is Gulliver, with a diameter of 3.4 miles.
  18. Phobos is expected to be destroyed by tidal forces or a collision with Mars in the next 30 to 50 million years.

Additional Resources on the Moon Phobos