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 Case for Mars to silver which have not been subjected to millennia of human scavenging and may be sold on Earth for profit. Secondly, the concentration of deuterium – a possible fuel for commercial nuclear fusion – is five times greater on Mars. Humans emigrating to Mars thus have an assured industry and the planet will be a magnet for settlers as wage costs will be high. The book asserts that “the labor shortage that will prevail on Mars will drive Martian civilization toward both technological and social advances.” While detailing the exploration and colonization, "The Case for Mars" also addresses a number