Phobos


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Related to Phobos: Deimos

Phobos

(fō`bŏs), in astronomy, innermost moon, or natural satellite, of MarsMars,
in astronomy, 4th planet from the sun, with an orbit next in order beyond that of the earth. Physical Characteristics

Mars has a striking red appearance, and in its most favorable position for viewing, when it is opposite the sun, it is twice as bright as
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.

Phobos

(foh -bos) The innermost and larger of the two satellites of Mars, both of which were discovered in 1877 by Asaph Hall. Observations from Mars-orbiting spacecraft show it to be an irregular potato-shaped body, measuring 27 × 22 × 19 km with a mass of 1016 kg and a density twice that of water. It orbits above the equator of Mars at a distance of 9380 km from the center of the planet every 7.65 hours, keeping its long axis pointing toward Mars. The low density, together with a low albedo of 0.06, suggest that it resembles the water-rich carbonaceous chondrite meteorites, although it is difficult to see how such an object could have formed at the distance of Mars from the Sun. Possibly Phobos and Deimos, Mars' other small satellite, formed as more distant asteroids and were later captured by Mars in some way. The orbit of Phobos is decaying (contracting) because of tidal drag and the satellite may fall from orbit within another 100 million years.

Phobos has a regolith-covered cratered surface with the two largest craters, Stickney and Hall, having diameters of 10 and 6 km. A network of pitted grooves, typically 100–200 meters wide and 20–30 meters deep, radiate around the satellite from Stickney and are thought to have arisen from severe internal fracturing and heating caused by the impact event that formed the crater. Chains of small craters parallel to the orbit of Phobos possibly represent the secondary impacts of clumps of material swept up from orbit around Mars after being ejected from the satellite during earlier primary impacts. See Table 2, backmatter.

Phobos

 

the innermost satellite of the planet Mars, located at a mean distance of 9,380 km from the planet. According to photographs obtained by the space probe Mariner 9 in 1971–72, Phobos is an irregularly shaped body pitted with numerous craters. It measures 26 km in length and 21 km in width. Its period of revolution around Mars is 7 hr 39 min, that is, less than the period of rotation of Mars about its axis. The albedo of Phobos’ surface is close to the albedo of the darkest areas of the moon (about 5 percent). Phobos was discovered by A. Hall in 1877.

Phobos

[′fō‚bȯs]
(astronomy)
A satellite of Mars; it is the larger of the two satellites, with a diameter of about 15 miles (24 kilometers).
References in periodicals archive ?
USA], Jul 21 ( ANI ): NASA's Hubble Space Telescope has captured Phobos, one of Mars' two moons, during its orbital trek around the Red Planet.
Those moons, long since reclaimed by Mars, could have herded remaining debris in the sparsely populated outer part of the ring to form Phobos and Deimos.
Melosh led a team chosen by NASA's Planetary Protection Office to evaluate if a sample from Phobos could contain enough recent material from Mars to include viable Martian organisms.
Phobos-Grunt was designed to collect and return soil samples from Mars's moon Phobos.
It is designed to travel to the Martian moon of Phobos, scoop up soil and return the sample to Earth by 2014.
Seriously, though, Grunt translates as Earth or soil, and Phobos is the name of one of Mars' moons - the Russian probe's destination.
The craft was aiming to get ground samples from Phobos, one of Mars' two moons.
The craft was due to land on Phobos, a moon of Mars, and take mineral samples in what was billed as the most challenging unmanned interplanetary mission ever.
Dutch ICT company Simac Techniek (AMS:SIMAC) has completed its previously proposed acquisition of sector firm Phobos Groep BV, the buyer said without providing financial details.
4 May 2011 - Dutch ICT firm Simac Techniek NV (AMS:SIMAC) said today it expects to complete the acquisition of local peer Phobos Groep BV in the coming few weeks.
1877 Astronomer Asaph Hall discovered Phobos and Deimos - the 'moons' of Mars.
The Martian moon Phobos is cratered, lumpy and about 16.