Mars
Mars is the fourth planet from the Sun and the seventh largest in the Solar System. A cold, dusty desert world with a thin atmosphere (mostly CO₂), the planet features extinct volcanoes, deep canyons, polar ice caps, and seasons. Mars has two small moons (Phobos and Deimos), a day just over 24 hours long, and a year lasting about 687 Earth days. It is a prime focus of robotic exploration and studies about past water and habitability.
Source: science.nasa.gov
APODs including "Mars"
At Work on Mars
14/07/1998
To learn about the history ofMars, just ask the rocks. Last year, that's exactly what the robot rover Sojourner did. Sojouner can be seen, above, analyzing a rock nicknamed Moe, trying to discern its past. One significant discovery of the Mars Pathfinder mission was that of conglomerate rocks, indicating the presence of running water in the past. Such water, in turn, indicates that Mars was much more like watery Earth in the distant past. Visible in the foreground of this color-enhanced mosaic is part of the Sagan Memorial Station, while a hill nicknamed one of the "Twin Peaks" is visible about a kilometer in the distance.