What are the Names of Mars Moons?

Mars has two small moons named Phobos and Deimos.  These moons were discovered in 1877 by American astronomer Asaph Hall.  They are irregularly shaped and are much smaller compared to moons like Earth’s moon, Ganymede of Jupiter, or Titan of Saturn.

Characteristics and Features

Phobos

• • Size:  It is the larger of the two moons, with an average diameter of about 22.4 km (13.9 miles).
  • Orbit:  Phobos is extremely close to Mars, orbiting at a distance of around 9,378 km (5,827 miles) from the planet’s surface.
  • Orbital Period:  It orbits Mars at a rapid pace, taking just about 7.66 hours to complete one orbit.
  • Notable Features:  One of the most striking features of Phobos is the Stickney crater, which has a diameter of about 9 km (5.6 miles).

Deimos

• • Size:  Deimos is the smaller moon, with dimensions measuring roughly 12.4 km × 12.2 km × 11.4 km.
  • Orbit:  It orbits Mars at a greater distance, about 23,460 km (14,580 miles) from the Martian surface.
  • Orbital Period:  Deimos takes about 30.3 hours to complete one orbit around Mars.
  • Notable Features:  Unlike Phobos, Deimos has a smoother surface and lacks large, prominent craters.

Origin Theories

The origin of these moons is still a subject of scientific debate:

• Captured Asteroids:  The most popular theory is that both Phobos and Deimos are captured asteroids from the asteroid belt between Mars and Jupiter.

• Mars-Origin:  Another theory posits that the moons might have formed from debris thrown into Martian orbit after a massive impact.

• Kuiper Belt Objects:  There are also theories that suggest they might be captured trans-Neptunian objects from the Kuiper Belt.

Names and Mythology

• Phobos:  The name “Phobos” is derived from Greek mythology and translates to “fear” or “panic.”  In mythology, Phobos is the son of Ares (Mars in Roman mythology) and Aphrodite (Venus in Roman mythology).  Phobos is said to accompany his father into battle.

• Deimos:  Similarly, the name “Deimos” translates to “dread” or “terror” in Greek.  Like Phobos, Deimos is also a son of Ares and Aphrodite and is said to accompany his father in war.

These names are fitting for moons of Mars, the Roman god of war, echoing the emotional aspects of battle.

Check out our 3D Mars Learning Center for more information on Mars.   You can also learn more at: NASA Mars Exploration.