Mars posters and prints from Zazzle.
The Rover Opportunity on Mars Poster by Space_Exploration
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The Red Planet: Super Panorama Frieze Poster by Graham_Conrad
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Evidence of a Watery Past on Mars Print by Space_Exploration
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Mars Rover Spirit's Destination: Columbia Hills Posters by Space_Exploration
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Guide to Rock Outcrop Near Mars Rover Opportunity Posters by Space_Exploration
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The Rover Opportunity on Mars Poster by Space_Exploration
Browse other Hubble space telescope Posters
The Red Planet: Super Panorama Frieze Poster by Graham_Conrad
Make custom prints online at zazzle.com
Evidence of a Watery Past on Mars Print by Space_Exploration
View more Hubble space telescope Posters
Mars Rover Spirit's Destination: Columbia Hills Posters by Space_Exploration
View other Hubble space telescope Posters
Guide to Rock Outcrop Near Mars Rover Opportunity Posters by Space_Exploration
Look for more gallery posters at Zazzle
See other gifts available on Zazzle.
Mars is the fourth planet from the Sun in the Solar System. Named after the Roman god of war, Mars, it is often described as the "Red Planet" as the iron oxide prevalent on its surface gives it a reddish appearance. Mars is a terrestrial planet with a thin atmosphere, having surface features reminiscent both of the impact craters of the Moon and the volcanoes, valleys, deserts, and polar ice caps of Earth. The rotational period and seasonal cycles of Mars are likewise similar to those of Earth, as is the tilt that produces the seasons. Mars is the site of Olympus Mons, the highest known mountain within the Solar System, and of Valles Marineris, one of the largest canyons. The smooth Borealis basin in the northern hemisphere covers 40% of the planet and may be a giant impact feature. Mars has two moons, Phobos and Deimos, which are small and irregularly shaped. These may be captured asteroids, similar to 5261 Eureka, a Martian trojan asteroid.
Until the first successful flyby of Mars occurred in 1965, by Mariner 4, many speculated about the presence of liquid water on the planet's surface. This was based on observed periodic variations in light and dark patches, particularly in the polar latitudes, which appeared to be seas and continents; long, dark striations were interpreted by some as irrigation channels for liquid water. These straight line features were later explained as optical illusions, though geological evidence gathered by unmanned missions suggest that Mars once had large-scale water coverage on its surface. In 2005, radar data revealed the presence of large quantities of water ice at the poles, and at mid-latitudes. The Mars rover Spirit sampled chemical compounds containing water molecules in March 2007. The Phoenix lander directly sampled water ice in shallow Martian soil on July 31, 2008.
http://en.wikipedia.org/wiki/Mars 
