Mars

Mars is the fourth planet from the Sun and it is the seventh largest planet in the solar system. Its axial inclination is similar, giving it seasons like Earth. Polar ice caps expand and recede. Mars has less gravity and atmosphere with similar cloud types. Its dormant volcanoes are the largest in our solar system. Mars has two moons, Phobos and Deimos.Mars - Planets & Astronautic Development in China
For a planet to have liquid water, it must be the perfect distance from the Sun, not so close that it boils away, and not so far that it freezes.
There is no liquid water on Mars, it is generally far too cold and the atmospheric pressure is too low. While there are certain places (near the equator) on Mars that occasionally reach temperatures high enough for liquid water to exist, the atmospheric pressure is so low that any ice on the ground surface would change directly from ice into vapor, which is called sublimation.
==Roman God of War==
Mars was the son of Juno and a magical herb, the Roman god of war. Mars was also the father of Romulus and Remus, the founders of Rome. For this reason, Mars was one of the most widely worshiped gods among the Roman people.
==Canyon==
Valles Marineris is the largest canyon in the Solar System. It extends over 3,000 kilometers long, spans as much as 600 kilometers across, and delves as much as 8 kilometers deep. By comparison, the Earth's Grand Canyon in Arizona, USA is 800 kilometers long, 30 kilometers across, and 1.8 kilometers deep. The origin of the Valles Marineris remains unknown, although a leading hypothesis holds that it started as a crack billions of years ago as the planet cooled. Recently, several geologic processes have been identified in the canyon.APOD: 2002 August 27APOD: 2003 August 24APOD: 2006 July 30APOD: 2011 March 27APOD: 2014 May 11
==Largest Volcano==
Olympus Mons is the largest volcano in the Solar System is on Mars. It rises 24 kilometers high and measures 550 km across. By comparison, Earth's largest volcano, Mauna Loa in Hawaii, rises 9 km high and measures 120 km across. Such large volcanoes can exist on Mars because of the low gravity and lack of surface tectonic motion. Olympus Mons is a shield volcano, built by fluid lava.APOD: September 15 1997
==Life on Mars?==
For centuries people have speculated about the possibility of life on Mars owing to the planet's proximity and similarity to Earth. Serious searches for evidence of life began in the 19th century, and continue via telescopic investigations and landed missions. While early work focused on phenomenology and bordered on fantasy, modern scientific inquiry has emphasized the search for chemical biosignatures of life in the soil and rocks at the planet's surface, and the search for biomarker gases in the atmosphere. Fictional Martians have been a recurring feature of popular entertainment of the 20th and 21st centuries, and it remains an open question whether life currently exists on Mars, or has existed there in the past.
==References==
 
Category:Astronomical objects known since antiquity
Category:Terrestrial planets