Meet Mars little Moons

When people think of Mars they don't usually think about the Moons of Mars. But sure enough Mars has 2 little Moons named Phobos and Deimos. Both were discovered in 1877 by the American astronomer Asaph Hall. Unfortunatly they are 2 small to see with the naked eye or even the best home based telescopes but we have lots of great pitures of them from the many unmaned probes we have sent to Mars.


Mars larger moon Phobos spins around it’s planet closer than any other moon in our solar system. It orbits at a very close 3700 miles (6000km) from the Mars surface. Because of this proximity it orbits the planet every 7 hours making it one of the fastest orbiting moon in our solar system. Mars is slowly pulling the small moon closer. Every hundred years the moon is pulled 6.6 feet (2 meters) closer to Mars. Scientist speculate that the moon is slowly being pulled apart by the gravitational tidal forces and point to the grooves seen on the surface as evidence of this. It’s estimated that poor Phobos will crumble into small pieces within the next 30 to 40 million years.

Phobos is the larger of Mars 2 moons. It orbits closer to Mars then it's sister moon Deimos.

Dimensions: 27 × 22 × 18 km Diameter:  22.2 km
Mean radius: 11.2667 km
Mass: 1.07 × 10^16 kg
Volume : 5783.61 km3 Orbit Distance: 3,700 km
Orbit Period: 7h 39.2min
Ave. orbital speed: 2.138 km/s Surface Temperature: -40 °C
Atmosphere: none


Mars smaller moon Deimos is most likely an astroid that was cast out of the Astroid belt by Jupiter's gravity and captured by Mars. It’s orbit is very circular and follows close to Mars equatorial plan. Deimos surface is smoother than it’s sister Phobos but is still marked with craters. Like other body’s of this size it is very non-spherical because it goes not posses enough gravity to pull it’s mass into a sphere.

Deimos is Mars smaller moon at about half the size of Phobos. It's orbit is 14k further from the surface that it's sister moon.

Dimensions: 15 × 12.2 × 11 km Diameter:  12 km
Mean radius: 6.2 ± 0.18 km
Mass: 1.4762 × 1015 kg
Volume : 999.78 km3 Orbit Distance: 23,460 km
Orbit Period: 30 h
Ave. orbital speed: 1.3513 km/s Surface Temperature: -40 °C
Atmosphere: none