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A transit of Phobos across the Sun as seen from Mars takes place when Phobos passes directly between the Sun and a point on the surface of Mars, obscuring a large part of the Sun's disc for an observer on Mars. During a transit, Phobos can be seen from Mars as a large black disc rapidly moving across the face of the Sun. At the same time, the ...
Phobos (/ ˈ f oʊ b ə s /; systematic designation: Mars I) 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 Greek god of fear and panic, who is the son of Ares (Mars) and twin brother of Deimos.
Observers on Mars can also view lunar eclipses of Phobos and Deimos. Phobos spends about an hour in Mars's shadow; for Deimos it is about two hours. Surprisingly, despite its orbit being nearly in the plane of Mars's equator and despite its very close distance to Mars, there are some occasions when Phobos escapes being eclipsed.
The history of Mars observation is about the recorded history of observation of the planet Mars. Some of the early records of Mars' observation date back to the era of the ancient Egyptian astronomers in the 2nd millennium BCE. Chinese records about the motions of Mars appeared before the founding of the Zhou dynasty (1045 BCE).
Phobos' Stickney Crater Deimos (lower left) and Phobos (lower right) compared with the asteroid 951 Gaspra Phobos by Mars Global Surveyor in 1998 [49] There have also have been proposed missions dedicated to explore the two moons of Mars, Phobos and Deimos. Many missions to Mars have also included dedicated observations of the moons, while this ...
Both sets of findings support an origin of Phobos from material ejected by an impact on Mars that reaccreted in Martian orbit, [40] similar to the prevailing theory for the origin of Earth's moon. The moons of Mars may have started with a huge collision with a protoplanet one third the mass of Mars that formed a ring around Mars.
Once in Mars orbit, PADME would carry out 16 flybys of Phobos followed by 9 flybys of Deimos. [5] Flybys would take place at two-week intervals. Flyby altitudes at closest approach to Phobos and Deimos would be ~2 km. [5] Following completion of its primary mission, PADME could remain in high Mars orbit for long-term monitoring of the martian system and search for potential additional moonlets ...
If Phobos has been orbiting for 4.3 Ga (billion years) then Stickney formed 4.2 Ga ago, but if Phobos has only been orbiting for 3.5 Ga then it formed 2.6 Ga ago. [4] The impact created a large amount of ejecta which escaped Phobos' gravity and entered into orbit around Mars for a period not exceeding 1000 years, some of this material then ...