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Mars comes closer to Earth more than any other planet save Venus at its nearest—56 million km is the closest distance between Mars and Earth, whereas the closest Venus comes to Earth is 40 million km. Mars comes closest to Earth every other year, around the time of its opposition, when Earth is sweeping between the Sun and Mars. Extra-close ...
Mars is the fourth planet from the Sun.The surface of Mars is orange-red because it is covered in iron(III) oxide dust, giving it the nickname "the Red Planet". [22] [23] Mars is among the brightest objects in Earth's sky, and its high-contrast albedo features have made it a common subject for telescope viewing.
Celestial north pole on Mars Celestial south pole on Mars The orientation of Mars's axis is such that its north celestial pole is in Cygnus at R.A. 21 h 10 m 42 s Decl. +52° 53.0′ (or more precisely, 317.67669 +52.88378), near the 6th-magnitude star BD +52 2880 (also known as HR 8106, HD 201834, or SAO 33185), which in turn is at R.A. 21 h ...
With an altitude of 5,989 km (3,721 mi), Phobos orbits Mars below the synchronous orbit radius, meaning that it moves around Mars faster than Mars itself rotates. [23] Therefore, from the point of view of an observer on the surface of Mars, it rises in the west, moves comparatively rapidly across the sky (in 4 h 15 min or less) and sets in the ...
Deimos (/ ˈ d aɪ m ə s /; systematic designation: Mars II) [11] is the smaller and outer of the two natural satellites of Mars, the other being Phobos. Deimos has a mean radius of 6.2 km (3.9 mi) and takes 30.3 hours to orbit Mars. [5] Deimos is 23,460 km (14,580 mi) from Mars, much farther than Mars's other moon, Phobos. [12]
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.
Observations of Mars had shown that the planet appeared to move 40% faster on one side of its orbit than the other, in conflict with the Aristotelian model of uniform motion. Ptolemy modified the model of planetary motion by adding a point offset from the center of the planet's circular orbit about which the planet moves at a uniform rate of ...
One can also speak of the motion of images, shapes, and boundaries. In general, the term motion signifies a continuous change in the position or configuration of a physical system in space. For example, one can talk about the motion of a wave or the motion of a quantum particle, where the configuration consists of the probabilities of the wave ...