Mars
Videos
Mars is the fourth planet from the Sun. It is also known as the "Red Planet", for its orange-red appearance. Mars is a desert-like rocky planet with a tenuous atmosphere that is primarily carbon dioxi
Valles Marineris, taken by the Viking 1 probe
Artist concept showing sand-laden jets erupting from Martian geysers (published by NASA; artist: Ron Miller)
Mars without a dust storm in June 2001 (on left) and with a global dust storm in July 2001 (on right), as seen by Mars Global Surveyor
Difference of dust and water clouds: the yellow cloud at the bottom center of the image is a large dust cloud, the other white clouds are water clouds.
Volcanism on Mars
Videos
Volcanic activity, or volcanism, has played a significant role in the geologic evolution of Mars. Scientists have known since the Mariner 9 mission in 1972 that volcanic features cover large portions
Mariner 9 image of Ascraeus Mons. This is one of the first images to show that Mars has large volcanoes.
THEMIS image of lava flows with lobate edges (from Arsia Mons volcano)
First X-ray diffraction view of Martian soil – CheMin analysis reveals minerals (including feldspar, pyroxenes and olivine) suggestive of "weathered basaltic soils" of volcanoes in Hawaii (Curiosity rover at "Rocknest", 2012). Each ring is a diffraction peak that corresponds to a specific atom-atom distance, which are unique enough to identify minerals. Smaller rings corresponds to larger features and vice versa.
Viking orbiter image of the three Tharsis Montes: Arsia Mons (bottom), Pavonis Mons (center), and Ascraeus Mons (top)