Search results
Results from the WOW.Com Content Network
The sixteen equatorial quadrangles are the smallest, with surface areas of 4,500,000 square kilometres (1,700,000 sq mi) each, while the twelve mid-latitude quadrangles each cover 4,900,000 square kilometres (1,900,000 sq mi). The two polar quadrangles are the largest, with surface areas of 6,800,000 square kilometres (2,600,000 sq mi) each.
Vesta (radius 262.7 ± 0.1 km), the second-largest asteroid, appears to have a differentiated interior and therefore likely was once a dwarf planet, but it is no longer very round today. [74] Pallas (radius 255.5 ± 2 km ), the third-largest asteroid, appears never to have completed differentiation and likewise has an irregular shape.
Substituting the mass of Mars for M and the Martian sidereal day for T and solving for the semimajor axis yields a synchronous orbit radius of 20,428 km (12,693 mi) above the surface of the Mars equator. [3] [4] [5] Subtracting Mars's radius gives an orbital altitude of 17,032 km (10,583 mi). Two stable longitudes exist - 17.92°W and 167.83°E.
For example, if a TNO is incorrectly assumed to have a mass of 3.59 × 10 20 kg based on a radius of 350 km with a density of 2 g/cm 3 but is later discovered to have a radius of only 175 km with a density of 0.5 g/cm 3, its true mass would be only 1.12 × 10 19 kg.
Mars has an orbit with a semimajor axis of 1.524 astronomical units (228 million km) (12.673 light minutes), and an eccentricity of 0.0934. [ 1 ] [ 2 ] The planet orbits the Sun in 687 days [ 3 ] and travels 9.55 AU in doing so, [ 4 ] making the average orbital speed 24 km/s.
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]
For planet Earth, which can be approximated as an oblate spheroid with radii 6 378.1 km and 6 356.8 km, the mean radius is = (( ) ) / = . The equatorial and polar radii of a planet are often denoted r e {\displaystyle r_{e}} and r p {\displaystyle r_{p}} , respectively.
The Eridania Basin, located near 180 E and 30 South, is thought to have contained a large lake with a depth of 1 km in places. [60] The basin is composed of a group of eroded and connected topographically impact basins. The lake has been estimated to have an area of 3,000,000 square kilometers.