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 Unusual Blueberries at Bylot Rock
17/08/2004
Why aren't these Martian rocks round? Small rocks dubbed blueberries have been found by the Opportunity rover all over Meridiani Planum on Mars, but the ones perched on Bylot rock have unusually non-spherical shapes. The strangely shaped blueberry rocks are shown above in an image taken by Opportunity's microscopic imager on August 9. Dark sand also covers much of Bylot rock. One hypothesis for the lack of blueberry roundness here is a coating relatively resistant to erosion. The average diameter of a blueberry is about 4 millimeters. The study of these and other rock features is allowing a better understanding of the wet past of ancient Mars.