geologia: Mars

Evidence: 94 • authority: 72

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 dioxide (CO2). At the average surface level the atmospheric pressure is a few thousandths of Earth's, atmospheric temperature ranges from −153 to 20 °C (−243 to 68 °F), and cosmic radiation is high. Mars retains some water, in the ground as well as thinly in the atmosphere, forming cirrus clouds, fog, frost, larger polar regions of permafrost and ice caps (with seasonal CO2 snow), but no bodies of liquid surface water. Its surface gravity is roughly a third of Earth's or double that of the Moon. Its…

Evidence: 35 • authority: 72

This is a list of the tallest mountains in the Solar System. This list includes peaks on all celestial bodies where significant mountains have been detected. For some celestial bodies, different peaks are given across different types of measurement. The Solar System's tallest mountain is possibly the Olympus Mons on Mars with an altitude of 21.9 to 26 km. The central peak of Rheasilvia on the asteroid Vesta is also a candidate to be the tallest, with an estimated height between 19 and 22 km from peak to base. A 25 km tall mountain-like peak was detected via an occultation on the trans-Neptunian object 307261 Máni, qualifying it as one of the tallest known mountains in the Solar System, thou…

Evidence: 27 • authority: 72

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 of the Martian surface. These features include extensive lava flows, vast lava plains, and, such as Olympus Mons, the largest known volcanoes in the Solar System. Martian volcanic features range in age from Noachian (>3.7 billion years) to late Amazonian (< 500 million years), indicating that the planet has been volcanically active throughout its history, and some speculate it probably still is so today. Both Mars and Earth are large, differentiated planets built from similar chondritic materia…

Evidence: 27 • authority: 72

Olympus Mons (; Latin for 'Mount Olympus') is a large shield volcano on Mars. As measured by the Mars Orbiter Laser Altimeter (MOLA), it is 21.287 kilometres (69,840 ft) high, about 2.5 times the elevation of Mount Everest above sea level. It is Mars's tallest volcano, its tallest planetary mountain, and is approximately tied with Rheasilvia on Vesta as the tallest mountain currently discovered in the Solar System. It is associated with the volcanic region of Tharsis Montes. It last erupted 25 million years ago. Olympus Mons is the youngest of the large volcanoes on Mars, having formed during the Martian Hesperian Period with eruptions continuing well into the Amazonian Period. It has been…

Evidence: 0 • authority: 94

Evidence: — • authority: 72

During the late 19th and early 20th centuries, it was erroneously believed that there were "canals" on the planet Mars. These were a network of long straight lines on Mars, observed by astronomers using early telescopes without photography, that were believed to be engineering works or waterways via the mistranslation of Schiaparelli’s term canali ("channels") into English as “canals.” Modern historians of science widely agree that the Martian canals were a perceptual and linguistic artifact, arising from telescope limitations combined with optical illusions. They were first described by the Italian astronomer Giovanni Schiaparelli during the opposition of 1877, and attested to by later obs…

Evidence: — • authority: 72

Valles Marineris (; Latin for Mariner Valleys, named after the Mariner 9 Mars orbiter of 1971–72 which discovered it) is a system of canyons that runs along the Martian surface east of the Tharsis region. At more than 4,000 km (2,500 mi) long, 200 km (120 mi) wide and up to 7 km (23,000 ft) deep, Valles Marineris is the largest canyon in the Solar System. Valles Marineris is located along the equator of Mars, on the east side of the Tharsis Bulge, and stretches for nearly a quarter of the planet's circumference. The canyon system starts in the west with Noctis Labyrinthus; proceeding to the east are Tithonium and Ius chasmata, then Melas, Candor and Ophir chasmata, then Coprates Chasma, the…

Evidence: — • authority: 92

Mars Perihelion Cloud Trails as revealed by MARCI: Mesoscale Topographically Focussed Updrafts and Gravity Wave Forcing of High Altitude Clouds.. Daily, global wide angle imaging of Mars clouds in MARCI (MARs Color Imager, (Malin et al., 2008)) ultraviolet and visible bands reveals the spatial/seasonal distributions and physical characteristics of perihelion cloud trails (PCT); a class of high altitude (40-50 km), horizontally extended (200-1000 km, trending W to WSW) water ice clouds formed over specific southern low-to-mid latitude (5S-40S), mesoscale (~50 km) locations during the Mars perihelion, southern summer season. PCT were first reported in association with rim regions of Valles Ma…