You are here

Mars' Moons

Mars has two small moons, Phobos and Deimos. Phobos is the larger of the two. It is shaped like a potato, about 15 miles long by 10 miles wide. One end is scarred by a giant crater. The impact that created it may have fractured the entire moon, leaving big cracks that travel from one end to the other. Phobos is in such a low orbit that it circles Mars about three times per day. It rises in the west, then sets in the east just a few hours later. As seen from the equator it looks less than half as big as our Moon looks from Earth. Deimos is both smaller and farther out. It takes almost three days to complete one orbit. From the Martian surface, it looks about like Venus looks from Earth.


Mars' Moons February 19, 2016


Mars February 10, 2016

Radio Programs

Moon and Mars Whipping up the moons of Mars September 9, 2016

Moon and Mars Breaking up a small moon January 31, 2016

Moon and Companions Stirring up two Martian moons January 30, 2016

Moon and Planets Profiling undiscovered moons September 27, 2014

Mars Companions Distant companions for the Red Planet November 30, 2013

More Moon and Mars Taking a ride on a Martian moon January 12, 2013

Phobos-Grunt DNA testing for a Martian moon November 3, 2011

Moon and Mars Twin moons under alien skies September 21, 2011

Birth of a Moon New ideas about the birth of a moon April 14, 2011

Featured Images

High-resolution view of Phobos, moon of Mars

Doomed Moon January 13, 2013

The Russian Phobos-Grunt Mars mission launches on November 8, 2011

Phobos Flop? November 11, 2011

The moon Phobos floats above Mars

Martian Target November 3, 2011

Phobos, one of the moons of Mars, passes by the planet Jupiter.

Out of Order June 20, 2011