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"
The Exploration of Mars
16/07/1995
July 16, 1995 The Exploration of Mars Picture Credit: NASA,Viking Project, USGS Explanation: Thirty years ago NASA's exploration of Mars began. In July of 1965 the Mariner 4 spacecraft flew within 6,000 miles of Mars and returned 21 pictures of the mysterious red planet. NASA's continued exploration of Mars has produced detailed views of the red tinged Martian surface like the one shown above which is a composite of 102 images from the Viking missions to Mars . The composite was constructed by the US Geological Survey. For more information about the picture see the NSSDC Photo Gallery of Mars. The exploration of Mars is chronicled by the Center For Mars Exploration. We keep an archive of Astronomy Pictures of the Day. Astronomy Picture of the Day is brought to you by Robert Nemiroff and Jerry Bonnell . Original material on this page is copyrighted to Robert J. Nemiroff and Jerry T. Bonnell.