Phobos (moon)
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Phobos is the innermost and larger of the two natural satellites of Mars, the other being Deimos. The two moons were discovered in 1877 by American astronomer Asaph Hall. Phobos is named after the Gre
A false color composite image of Phobos captured by the Mars Reconnaissance Orbiter in 2008
Deimos and Phobos as seen from Mars, compared in apparent size to the Moon as seen from Earth
An artist's concept of Martian Moons eXploration spacecraft
The Phobos monolith (right of center) as taken by the Mars Global Surveyor (MOC Image 55103, 1998)
Mars
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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
Phobos (moon)
…mi). It orbits 6,000 km (3,700 mi) from the Martian surface, closer to its primary body than any other known natural satellite to a planet. It orbits Mars much faster than Mars rotates and completes an orbit in just 7 hours and 39 minutes. As a result, from the surface of Mars it appears to rise in the…
Valles Marineris, taken by the Viking 1 probe
Artist concept showing sand-laden jets erupting from Martian geysers (published by NASA; artist: Ron Miller)
A 30 meter wide and 800 meter high dust devil. Dust devils of 20 kilometer height have been observed.
Dust devils cause twisting dark trails on the Martian surface