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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 ...
The corresponding values for Earth are currently 23 h 56 m 4.0916 s and 24 h 00 m 00.002 s, respectively, which yields a conversion factor of 1.027 491 2517 Earth days/sol: thus, Mars's solar day is only about 2.75% longer than Earth's; approximately 73 sols pass for every 75 Earth days.
The time unit ([CTU]) can be converted to another unit system for a more useful qualitative solution using the following equation: = For Earth-orbiting satellites, approximate unit conversions are as follows: 1 [CDU] = 6378.1 km = 20,925,524.97 ft
Distances between the planets in the Solar System are often measured in astronomical units (AU), defined as the average distance between the Sun and Earth, some 1.5 × 10 8 kilometers (93 million miles). Venus, the closest planet to Earth is (at closest approach) 0.28 AU away. Neptune, the farthest planet from the Sun, is 29.8 AU away.
While the Kármán line is defined for Earth only, several scientists have estimated the corresponding figures for Mars and Venus. Isidoro Martínez arrived at 80 km (50 miles) and 250 km (160 miles) high, respectively, [31] while Nicolas Bérend arrived at 113 km (70 miles) and 303 km (188 miles). [32]
≡ Time of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom at 0 K [8] (but other seconds are sometimes used in astronomy). Also that time it takes for light to travel a distance of 299 792 458 metres. (SI base unit) shake: ≡ 10 −8 s = 10 ns ...
At their furthest Mars and Earth can be as far as 401 million km (249 million mi) apart. [191] Mars comes into opposition from Earth every 2.1 years. The planets come into opposition near Mars's perihelion in 2003, 2018 and 2035, with the 2020 and 2033 events being particularly close to perihelic opposition. [192] [193] [194]
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.