Mars

Mars (pronounced /'m?rz/) is the fourth planet from the Sun in the planetary System. The planet is name after Mars, the Roman god of war. It is also named as the "Red Planet" because of its reddish form as seen from Earth.

Mars is a terrestrial planet with a thin atmosphere, having surface features suggestive both of the impact craters of the Moon and the volcanoes, valleys, deserts and polar ice caps of Earth. It is the site of Olympus Moons, the highest known mountain in the Solar System, and of Valleys Mariners, the largest canyon. In addition to its geographical features, Mars’ rotational period and seasonal cycles are likewise alike to those of Earth.

Until the first flyby of Mars by Mariner 4 in 1965, it was speculate that there might be liquid water on the planet's surface. This was based on observations of periodic variation in light and dark patches, mainly in the polar latitudes, which looked like seas and continents, while long, dark striations were interpreted by some observer as irrigation channels for liquid water. These straight line features were later proven not to exist and were instead explain as optical illusions. Still, of all the planets in our Solar System further than Earth, Mars is the most likely to harbor liquid water, and perhaps life.