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Encyclopedia > Deimos (moon)
Deimos
Deimos
An image of Deimos taken by the Viking 1 orbiter.
Discovery
Discovered by Asaph Hall
Discovered on August 12, 1877
Orbital characteristics
Mean radius 23,460 km
Eccentricity 0.0002
Revolution period 1.262 d
Avg. Orbital Speed 0.22 km/s
Inclination 0.93° (to Mars' equator)
1.793° (to the local Laplace plane)
27.58° (to the ecliptic)
Satellite of Mars
Physical characteristics
Mean diameter 12.6 km (15.0×12×10.4)
Mass 2.244×1015 kg
Mean density 2.2 g/cm3
Surface gravity 0.0039 m/s² (3.9 mm/s²)
Surface Gravity
(Earth = 1)
0.00040 (400 µg)
Escape velocity 0.0069 km/s (6.9 m/s)
Rotation period synchronous
Albedo 0.07
Surface temp. ≈233 K
Atmospheric pressure no atmosphere

Deimos (IPA /ˈdaɪməs/ or /ˈdiːməs/; Greek Δείμος: "Dread"), is the smaller and outermost of Mars’ two moons, named after Deimos from Greek Mythology. It is also known as Mars II. An image of Deimos taken by the Viking 1 orbiter. ... Asaph Hall (October 15, 1829 – November 22, 1907) was an American astronomer who is most famous for having discovered the moons of Mars (namely Deimos and Phobos) in 1877. ... August 12 is the 224th day of the year (225th in leap years) in the Gregorian Calendar. ... 1877 was a common year starting on Monday (see link for calendar). ... In physics, an orbit is the path that an object makes, around another object, whilst under the influence of a source of centripetal force, such as gravity. ... RADIUS (Remote Authentication Dial In User Service) is an AAA (authentication, authorization and accounting) protocol for applications such as network access or IP mobility. ... A kilometer (Commonwealth spelling: kilometre), symbol: km is a unit of length in the metric system equal to 1,000 metres (from the Greek words χίλια (khilia) = thousand and μέτρο (metro) = count/measure). ... In astrodynamics, under standard assumptions any orbit must be of conic section shape. ... Inclination in general is the angle between a reference plane and another plane or axis of direction. ... The Laplace plane is defined as the mean plane occupied by the orbit of a satellite during a precession cycle. ... The plane of the ecliptic is well seen in this picture from the 1994 lunar prospecting Clementine spacecraft. ... Moons of solar system scaled to Earths Moon A natural satellite is a moon (not capitalized), that is, any natural object that orbits a planet. ... Mars is the fourth planet from the Sun in the solar system, named after the Roman god of war (the counterpart of the Greek Ares), on account of its blood red color as viewed in the night sky. ... For the geometric term, see diameter. ... Mass is a property of a physical object that quantifies the amount of matter it contains. ... The international prototype, made of platinum-iridium, which is kept at the BIPM under conditions specified by the 1st CGPM in 1889. ... Density (symbol: ρ - Greek: rho) is a measure of mass per unit of volume. ... Gravity is a force of attraction that acts between bodies that have mass. ... Acceleration is the time rate of change of velocity, and at any point on a v-t graph, it is given by the slope of the tangent to that point In physics, acceleration (symbol: a) is defined as the rate of change (or derivative with respect to time) of velocity. ... In physics, for a given gravitational field and a given position, the escape velocity is the minimum speed an object without propulsion, at that position, needs to have to move away indefinitely from the source of the field, as opposed to falling back or staying in an orbit within a... In astronomy, synchronous rotation is a planetological term describing a body orbiting another, where the orbiting body takes as long to rotate on its axis as it does to make one orbit; and therefore always keeps the same hemisphere pointed at the body it is orbiting. ... Albedo is the measure of reflectivity of a surface or body. ... Temperature is also the name of a song by Sean Paul. ... The kelvin (symbol: K) is the SI unit of temperature, and is one of the seven SI base units. ... diurnal (daily) rhythm of air pressure in northern Germany (black curve is air pressure) Atmospheric pressure is the pressure above any area in the Earths atmosphere caused by the weight of air. ... This is a concise version of the International Phonetic Alphabet for English sounds. ... Mars is the fourth planet from the Sun in the solar system, named after the Roman god of war (the counterpart of the Greek Ares), on account of its blood red color as viewed in the night sky. ... Moons of solar system scaled to Earths Moon A natural satellite is a moon (not capitalized), that is, any natural object that orbits a planet. ... In Greek mythology, Deimos (dread) was the personification of dread. ... // Greek mythology consists of a large collection of narratives that explain the origins of the world and detail the lives and adventures of a wide variety of gods, goddesses, heroes, and heroines. ...

Contents


Discovery

Phobos and Deimos were both discovered by American astronomer Asaph Hall. The names were suggested by Henry Madan (1838–1901), Science Master of Eton, from Book XV of the Iliad, where Ares (the Roman god Mars) summons Dread (Deimos) and Fear (Phobos). Phobos (IPA , Greek Φόβος: Fright), is the larger and innermost of Mars two moons, and is named after Phobos, son of Ares (Mars) from Greek Mythology. ... Asaph Hall (October 15, 1829 – November 22, 1907) was an American astronomer who is most famous for having discovered the moons of Mars (namely Deimos and Phobos) in 1877. ... The Kings College of Our Lady of Eton beside Windsor, commonly known as Eton College or just Eton, is a prestigious and internationally known independent school for boys, which is often described as the most famous school in the world. ... The Iliad (Ancient Greek: Ιλιάς, Iliás) tells part of the story of the siege of the city of Ilium, i. ... In Greek mythology, Ares (battle strife; in Greek, Ἀρης), is the god of war and son of Zeus(king of the gods) and Hera . ... Mars was the Roman god of war, the son of Juno and a magical flower (or Jupiter). ... In Greek mythology, Deimos (dread) was the personification of dread. ... In Greek mythology, Phobos (fright) was the personification of fear and horror. ...


Deimos was discovered on August 12, 1877 at about 07:48 UTC (given in contemporary sources as "August 11 14:40" Washington mean time using the old astronomical convention of beginning a day at noon, so 12 hours must be added to get the actual local mean time) [1]. August 12 is the 224th day of the year (225th in leap years) in the Gregorian Calendar. ... 1877 was a common year starting on Monday (see link for calendar). ... It has been suggested that leap second be merged into this article or section. ... August 11 is the 223rd day of the year (224th in leap years) in the Gregorian Calendar. ... Washington mean time was the time observed at the US Naval Observatory at Washington, D.C. It was sometimes called Washington meridian time. The modern-day observatory code for the US Naval Observatory (before 1893) is 787, and the longitude was 77. ...


Characteristics

Deimos transits the Sun, as seen by Mars Rover Opportunity
Enlarge
Deimos transits the Sun, as seen by Mars Rover Opportunity

Deimos is probably an asteroid that was perturbed by Jupiter into an orbit that allowed it to be captured by Mars, though this hypothesis is still in some dispute. Like most bodies of its size, Deimos is highly nonspherical with dimensions of 15×12×10 km. A transit of Deimos from Mars: Deimos is in transit across the Sun, as seen from Mars by Mars Rover Opportunity on March 4, 2004 at 03:03:43 UTC Earth time. ... A transit of Deimos from Mars: Deimos is in transit across the Sun, as seen from Mars by Mars Rover Opportunity on March 4, 2004 at 03:03:43 UTC Earth time. ... Deimos transits the Sun, as seen by Mars Rover Opportunity on March 4, 2004 The word transit has two meanings in astronomy: A transit is the astronomical event that occurs when one celestial body appears to move across the face of another celestial body, as seen by an observer at... The Sun is the star at the center of Earths solar system. ... MER-B (Opportunity) is the second of the two rovers of NASAs Mars Exploration Rover Mission. ... Atmospheric characteristics Atmospheric pressure 70 kPa Hydrogen ~86% Helium ~14% Methane 0. ... In physics, an orbit is the path that an object makes, around another object, whilst under the influence of a source of centripetal force, such as gravity. ...


Deimos is composed of carbon-rich rock, much like C-type (carbonaceous chondrite) asteroids, and ice. It is cratered, but the surface is noticeably smoother than that of Phobos, caused by the partial filling of craters with regolith. The two largest craters, Swift and Voltaire, measure about 3 kilometres across. General Name, Symbol, Number carbon, C, 6 Chemical series nonmetals Group, Period, Block 14, 2, p Appearance black (graphite) colorless (diamond) Atomic mass 12. ... C-type asteroids are carbonaceous asteroids. ... Some carbonaceous chondrites. ... An asteroid is a small, solid object in our Solar System, orbiting the Sun. ... Tycho crater on Earths moon. ... Regolith (Greek: blanket rock) is a layer of loose, heterogeneous material covering solid rock. ...


As seen from Deimos, Mars would be 1000 times larger and 400 times brighter than the full Moon as seen from Earth, taking up a full 1/11 of the width of a celestial hemisphere. Bulk composition of the moons mantle and crust estimated, weight percent Oxygen 42. ...


As seen from Mars, Deimos has an angular diameter of no more than 2.5' and would therefore appear starlike to the naked eye. At its brightest ("full moon") it would be about as bright as Venus is from Earth; at the first or third quarter phase it would be about as bright as Vega. When Deimos passes in front of the Sun its angular diameter is only about 2.5 times the angular diameter for Venus during a transit of Venus from Earth. With a small telescope, a Martian observer could see Deimos' phases, which take 1.2648 days to run their course (Deimos' synodic period). (*min temperature refers to cloud tops only) Atmospheric characteristics Atmospheric pressure 9. ... Vega (also known as Alpha Lyrae or 3 Lyrae) is a star approximately 25. ... Deimos transits the Sun, as seen by Mars Rover Opportunity on March 4, 2004 A transit of Deimos across the Sun as seen from Mars takes place when Deimos passes directly between the Sun and a point on the surface of Mars, obscuring a small part of the Suns... The 2004 transit of Venus A transit of Venus across the Sun takes place when the planet Venus passes directly between the Sun and the Earth, obscuring a small portion of the Suns disc. ... The orbital period is the time it takes a planet (or another object) to make one full orbit. ...

Orbits of Phobos and Deimos (to scale)
Orbits of Phobos and Deimos (to scale)

Unlike Phobos, which orbits so fast that it actually rises in the west and sets in the east, Deimos rises in the east and sets in the west. However, the orbital period of Deimos of about 30.4 hours exceeds the Martian solar day ("sol") of about 24.7 hours by such a small amount that it takes 2.7 days between rising and setting for an equatorial observer. Image File history File links A simulated view of Naiad of the Orbits of Phobos and Deimos. ... Various schemes have been used or proposed to keep track of time and date on the planet Mars independently of Earth time and calendars. ...


Because Deimos' orbit is relatively close to Mars and has only a very small inclination to Mars' equator, it cannot be seen from Martian latitudes greater than 82.7°.




Deimos in fiction

  • In part 3 chapter 3 (the "Voyage to Laputa") of Jonathan Swift's famous satire Gulliver's Travels, a fictional work written in 1726, the astronomers of Laputa are described as having discovered two satellites of Mars orbiting at distances of 3 and 5 Martian diameters, respectively. The actual orbital distances of Phobos and Deimos are 1.4 and 3.5 Martian diameters, respectively. This is regarded as a fascinating coincidence; no telescope in Swift's day would have been even remotely powerful enough to discover these satellites.
  • In the comic Sailor Moon, Deimos is the name of one of two crows belonging to Sailor Mars.
  • Kim Stanley Robinson's Green Mars (1993) includes a detailed description of a manned landing on Deimos.
  • The second episode of the Computer and video game Doom takes place in a UAC base on Deimos. Before the beginning of the game, Deimos disappears from martian orbit, and is reached by the unnamed Marine after he steps into a large teleporter on Phobos. Eventually, it is discovered that Deimos is floating above Hell itself.
  • The UESC Marathon of the Marathon computer game series is a hollowed-out Deimos. Deimos' discovery in 1877 coincides with Bungie's tendency to use the number seven often.
  • In the GURPS Transhuman Space Roleplaying game source book about Mars, In The Well, they have placed an orbital elevator (Beanstalk) on Pavonis Mons, linked to Deimos.
  • One of the popular game series DOOM is set on Deimo, along with Phobo, the other moon on Mars.

Jonathan Swift Jonathan Swift (November 30, 1667 – October 19, 1745) was an Anglo-Irish priest, satirist, essayist, political pamphleteer, and poet famous for works like Gullivers Travels, A Modest Proposal, A Journal to Stella, The Drapiers Letters, The Battle of the Books, and A Tale of a Tub. ... Gulliver Gullivers Travels (1726, amended 1735) is a novel by Jonathan Swift that is both a satire on human nature and a parody of the travellers tales literary sub-genre. ... Events George Friderich Handel becomes a British subject. ... See comedian Stand up comedian List of Comedians List of British comedians comics comic book comic strip underground comics alternative comics web comic sprite comics manga graphic novel List of comic characters This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same... Sailor Moon ) is the title of the famous series originally authored as a manga by Naoko Takeuchi that resulted in multiple other types of media, including anime, musical theatre, video games and live action tokusatsu. ... Rei Hino Rei Hino (火野 レイ Hino Rei) is a Sailor Senshi, one of the main characters in the metaseries known as Sailor Moon. ... Kim Stanley Robinson at the 63rd World Science Fiction Convention in Glasgow, August 2005 Kim Stanley Robinson (born March 23, 1952) is an American science fiction writer, probably best known for his award-winning Mars trilogy. ... The Mars trilogy is a series of three science fiction novels by Kim Stanley Robinson, chronicling the settlement and terraforming of the planet Mars. ... 1993 (MCMXCIII) was a common year starting on Friday of the Gregorian calendar and marked the Beginning of the International Decade to Combat Racism and Racial Discrimination (1993-2003). ... This article is about computer and video games. ... Doom (or DOOM)[1] is a 1993 computer game by id Software that is among the landmark titles in the first-person shooter genre. ... Union Aerospace Corporation Logo in Doom 3 UAC Logo in Doom 2 The Union Aerospace Corporation (UAC) is a fictional military-industrial conglomerate, based in id Softwares Doom universe. ... Medieval illustration of Hell in the Hortus deliciarum manuscript of Herrad of Landsberg (about 1180) Hell, according to many religious beliefs, is a place or a state of pain and suffering. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... 1877 was a common year starting on Monday (see link for calendar). ... Bungie Studios is a video game developer founded in 1991 under the name Bungie Software by two undergraduate students at the University of Chicago, Alex Seropian and Jason Jones. ... 7 (seven) is the natural number following 6 and preceding 8. ... Doom (or DOOM)[1] is a 1993 computer game by id Software that is among the landmark titles in the first-person shooter genre. ...

References

See also

Phobos (IPA , Greek Φόβος: Fright), is the larger and innermost of Mars two moons, and is named after Phobos, son of Ares (Mars) from Greek Mythology. ... Mars is the fourth planet from the Sun in the solar system, named after the Roman god of war (the counterpart of the Greek Ares), on account of its blood red color as viewed in the night sky. ... This is a list of geological features on Phobos and Deimos, the moons of Mars. ... Deimos transits the Sun, as seen by Mars Rover Opportunity on March 4, 2004 A transit of Deimos across the Sun as seen from Mars takes place when Deimos passes directly between the Sun and a point on the surface of Mars, obscuring a small part of the Suns...

External links

edit Mars (satellites)

Phobos | Deimos Image File history File links Symbol_mars. ... For the Roman god, see Mars (mythology). ... Mars has two natural moons - Phobos and Deimos. ... Phobos (IPA , Greek Φόβος: Fright), is the larger and innermost of Mars two moons, and is named after Phobos, son of Ares (Mars) from Greek Mythology. ...

edit The Solar System
Planets: Mercury - Venus - Earth (Moon) - Mars - Jupiter - Saturn - Uranus - Neptune - Pluto
Other: Sun - Asteroid belt - Main-belt comets - Kuiper belt - Scattered disc - Oort cloud
See also astronomical objects and the solar system's list of objects, sorted by radius or mass.

  Results from FactBites:
 
Deimos (moon) - definition of Deimos (moon) in Encyclopedia (506 words)
Deimos was discovered on August 12, 1877 at about 07:48 UTC (given in contemporary sources as "August 11 14:40" Washington mean time using the old astronomical convention of beginning a day at noon, so 12 hours must be added to get the actual local mean time).
Deimos is probably an asteroid that was perturbed by Jupiter into an orbit that allowed it to be captured by Mars, though this theory is still in some dispute.
When Deimos passes in front of the Sun its angular diameter is only about 2.5 times the angular diameter for Venus during a transit of Venus from Earth.
Mars - Wikipedia, the free encyclopedia (4045 words)
Mars has two moons, Phobos and Deimos, which are small and oddly-shaped, and possibly captured asteroids.
Mars has two tiny natural moons, Phobos and Deimos, which orbit very close to the planet and are thought to be captured asteroids.
Both satellites were discovered in 1877 by Asaph Hall, and are named after the characters Phobos (panic/fear) and Deimos (terror/dread) who, in Greek mythology, accompanied their father Ares, god of war, into battle.
  More results at FactBites »

 
 

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