Flag of Mars "red Mars and two moons in blue field above a diagonal, white below". In Robert A. Heinlein's 1961 science-fiction novel "Stranger in a Strange Land", a flag of Mars is hastily improvised, consisting of "the field in white and the sigil of Mars in red". In The Expanse television series, based on "The Expanse" series of novels by James S. A. Corey, the Martian Congressional Republic is the governing body that rules over the inhabitants of Mars and is one of the two human superpowers in the series. Its flag is reminiscent of Mars and its two moons, Phobos and
Astrobiology restricted to the surfaces of planets. The three most likely candidates for life in the Solar System are the planet Mars, the Jovian moon Europa, and Saturn's moons Titan, and Enceladus. Mars, Enceladus and Europa are considered likely candidates in the search for life primarily because they may have underground liquid water, a molecule essential for life as we know it for its use as a solvent in cells. Water on Mars is found frozen in its polar ice caps, and newly carved gullies recently observed on Mars suggest that liquid water may exist, at least transiently, on the planet's