Solar eclipses on Mars Solar eclipses on Mars The two moons of Mars, Phobos and Deimos, are much smaller than the Moon, greatly reducing the frequency of solar eclipses on that planet. Neither moon's apparent diameter is large enough to cover the disk of the sun, and therefore they are annular solar eclipses and can also be considered transits. Due to the small size of Phobos (about ) and its rapid orbital motion, an observer on the surface of Mars would never experience a solar eclipse for longer than about thirty seconds. Phobos also takes only 7 hours 39 minutes to orbit Mars, while
The Secret of the Martian Moons that unlocks Mars’ secret. A political controversy is raging on Earth as to whether or not to continue to support the Martian outpost, where Nelson’s father is research chief. Those in favor point to the marvelous machines found on Mars, any one of which could advance civilization eons, if their secret could be discovered. Going to work on the problem, Nelson finds out – in an interesting chain of events that characterizes a Mars basically like the canal-covered red planet we know it to be now – that the Martian moons Phebos (sic) and Deimos, are centers of tyrannical factions