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Every opposition has some significance because Mars is visible from Earth all night, high and fully lit, but the ones of special interest happen when Mars is near perihelion, because this is when Mars is also nearest to Earth. One perihelic opposition is followed by another either 15 or 17 years later. In fact every opposition is followed by a ...
The altitude difference between the rim and the bottom is over 9,000 m (30,000 ft). Despite being deeper than the Moon's South Pole-Aitken basin , Hellas' rim peaks are significantly less prominent. This may be because large Martian impacts such as Hellas induced global hot rainfall and meltwater flows that degraded crater rims, including their ...
Mars has two permanent polar ice caps, the northern one located at Planum Boreum and the southern one at Planum Australe. The difference between Mars's highest and lowest points is nearly 30 km (from the top of Olympus Mons at an altitude of 21.2 km to Badwater Crater [1] at the bottom of the Hellas impact basin at an altitude of 8.2 km below ...
Mars hosts many enormous extinct volcanoes (the tallest is Olympus Mons, 21.9 km or 13.6 mi tall) and one of the largest canyons in the Solar System (Valles Marineris, 4,000 km or 2,500 mi long). Geologically, the planet is fairly active with marsquakes trembling underneath the ground, dust devils sweeping across the landscape, and cirrus clouds.
The maximum angular separation of the Earth and Moon varies considerably according to the relative distance between the Earth and Mars: it is about 25′ when Earth is closest to Mars (near inferior conjunction) but only about 3.5′ when the Earth is farthest from Mars (near superior conjunction). For comparison, the apparent diameter of the ...
Several factors make placing a spacecraft into an areostationary orbit more difficult than a geostationary orbit. Since the areostationary orbit lies between Mars's two natural satellites, Phobos (semi-major axis: 9,376 km) and Deimos (semi-major axis: 23,463 km), any satellites in the orbit will suffer increased orbital station keeping costs due to unwanted orbital resonance effects.
In gravitationally bound systems, the orbital speed of an astronomical body or object (e.g. planet, moon, artificial satellite, spacecraft, or star) is the speed at which it orbits around either the barycenter (the combined center of mass) or, if one body is much more massive than the other bodies of the system combined, its speed relative to the center of mass of the most massive body.
Many places on Mars show rocks arranged in layers. Rock can form layers in a variety of ways. Volcanoes, wind, or water can produce layers. [8] A detailed discussion of layering with many Martian examples can be found in Sedimentary Geology of Mars. [9] Layers can be hardened by the action of groundwater.