Moons of Mars satellites, Earth had one and Jupiter had four (known at the time), that Mars by analogy must have two. Furthermore, as they had not yet been discovered, it was reasoned that they must be small and close to Mars. This would lead Swift to making a roughly accurate estimate of their orbital distances and revolution periods. In addition Swift could have been helped in his calculations by his friend, the mathematician John Arbuthnot. Voltaire's 1752 short story "Micromégas", about an alien visitor to Earth, also refers to two moons of Mars. Voltaire was presumably influenced by Swift. In recognition of
Mars in culture in film. The theme of a Martian colony that fights for independence from Earth is a major plot element in the novels of Greg Bear as well as the movie "Total Recall" (based on a short story by Philip K. Dick) and the television series "Babylon 5". Some video games also use this element, including "Red Faction" and the "Zone of the Enders" series. Mars (and its moons) were also the setting for the popular "Doom" video game franchise and the later "Martian Gothic". Mars in culture Mars in culture is about the planet Mars in culture. For example, the