Amalthea

Galileo images of Amalthea
Discovery
Discovered by	E.E. Barnard
Discovery date	September 9, 1892
Orbital characteristics
Periapsis	181,150 km[1]
Apoapsis	182,840 km[1]
Mean orbit radius	181365. Galileo was an Unmanned spacecraft sent by NASA to study the Planet Jupiter and its moons Named after the Astronomer Edward Emerson Barnard ( December 16, 1857 – February 6, 1923) was an American Astronomer. Events 1000 - Battle of Svolder, Viking Age. 1379 - Treaty of Neuberg, splitting the Austrian Year 1892 ( MDCCCXCII) was a Leap year starting on Friday (link will display the full calendar of the Gregorian Calendar (or a Leap year In Physics, an orbit is the gravitationally curved path of one object around a point or another body for example the gravitational orbit of a planet around a star In Celestial mechanics, an apsis, plural apsides (ˈæpsɨdɪːz is the point of greatest or least distance of the Elliptical orbit of an object from In Celestial mechanics, an apsis, plural apsides (ˈæpsɨdɪːz is the point of greatest or least distance of the Elliptical orbit of an object from Remote Authentication Dial In User Service ( RADIUS) is a networking protocol that provides centralized access authorization and accounting management for people or computers 84 ± 0. 02 km (2. The kilometre ( American spelling: kilometer) symbol km is a unit of Length in the Metric system, equal to one thousand 54 RJ)[2]
Eccentricity	0. In Astrodynamics, under standard assumptions, any Orbit must be of Conic section shape 00319 ± 0. 00004[2]
Orbital period	0. The orbital period is the time taken for a given object to make one complete Orbit about another object 49817943 ± 0. 00000007 d (11 h 57 min 23 s)[2]
Average orbital speed	26. The orbital speed of a body generally a Planet, a Natural satellite, an artificial satellite, or a Multiple star, is the speed at which it 57 km/s[1]
Inclination	0. Inclination in general is the Angle between a Reference plane and another plane or axis of direction 374 ± 0. 002° (to Jupiter's equator)[2]
Satellite of	Jupiter
Physical characteristics
Dimensions	250 × 146 × 128 km³[3]
Mean radius	83. A natural satellite or moon is a Celestial body that Orbits a Planet or smaller body which is called the primary. 5 ± 2. 0 km[3]
Volume	(2. The volume of any solid plasma vacuum or theoretical object is how much three- Dimensional space it occupies often quantified numerically 43 ± 0. 22)×106 km³[4]
Mass	2. CM3 redirects here If you were looking for the 3rd game in the Cooking Mama series abbreviated as CM3 see here. Mass is a fundamental concept in Physics, roughly corresponding to the Intuitive idea of how much Matter there is in an object 08 ± 0. 15×1018 kg[4]
Mean density	0. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different 857 ± 0. 099 g/cm³[4]
Equatorial surface gravity	~0. The surface gravity, g, of an astronomical or other object is the Gravitational acceleration experienced at its surface 020 m/s² (~0. 002 g)[1]
Escape velocity	~0. In Physics, escape velocity is the speed where the Kinetic energy of an object is equal to the magnitude of its Gravitational potential energy 058 km/s[1]
Rotation period	synchronous[3]
Axial tilt	zero[3]
Albedo	0. The rotation period of an astronomical object is the time it takes to complete one revolution around its Axis of rotation relative to the background stars In Astronomy, synchronous rotation is a planetological term describing a body orbiting another where the orbiting body takes as long to rotate In Astronomy, axial tilt is the Inclination angle of a planet's rotational axis in relation to its orbital plane. The albedo of an object is the extent to which it diffusely reflects light from the sun 090 ± 0. 005[5]
Surface temp.    [7]	min mean max 120 K 165 K
Apparent magnitude	14. Temperature is a physical property of a system that underlies the common notions of hot and cold something that is hotter generally has the greater temperature The apparent magnitude ( m) of a celestial body is a measure of its Brightness as seen by an observer on Earth, normalized to the value 1[6]

Amalthea (pronounced /ˌæməlˈθiːə/ AM-əl-THEE-ə, Greek Αμάλθεια) is the third moon of Jupiter in order of distance from the planet. A natural satellite or moon is a Celestial body that Orbits a Planet or smaller body which is called the primary. It was discovered on September 9, 1892, by Edward Emerson Barnard and named after Amalthea, a nymph in Greek mythology. Events 1000 - Battle of Svolder, Viking Age. 1379 - Treaty of Neuberg, splitting the Austrian Year 1892 ( MDCCCXCII) was a Leap year starting on Friday (link will display the full calendar of the Gregorian Calendar (or a Leap year Edward Emerson Barnard ( December 16, 1857 – February 6, 1923) was an American Astronomer. In Greek mythology, Amalthea or Amaltheia ( Greek: Ἀμάλθεια is the most often mentioned among foster-mothers of Zeus. In Greek mythology, a nymph is any member of a large class of mythological entities in human female form Greek mythology is the body of stories belonging to the ancient Greeks concerning their gods and Heroes the nature of the world and the origins and significance ^[8] It is also known as Jupiter V.

Amalthea is in a close orbit around Jupiter and is within the outer edge of the Amalthea Gossamer Ring, which is formed from dust ejected from its surface. The planet Jupiter has a system of rings known as the rings of Jupiter or the Jovian ring system. ^[9] From its surface, Jupiter would be an astonishing sight in its sky, appearing 92 times larger than the full moon. Full moon is a Lunar phase that occurs when the Moon is on the opposite side of the Earth from the Sun. ^[10] Amalthea is the largest of the inner satellites of Jupiter. Irregularly shaped and reddish in colour, it is thought to consist of porous water ice with unknown amounts of other materials. Its surface features include large craters and high mountains. ^[3]

Amalthea was photographed in 1979 and 1980 by the Voyager 1 and 2 spacecraft, and later, in more detail, by the Galileo orbiter in the 1990s. Year 1979 ( MCMLXXIX) was a Common year starting on Monday (link displays the 1979 Gregorian calendar) Year 1980 ( MCMLXXX) was a Leap year starting on Tuesday (link displays the 1980 Gregorian calendar) See also Voyager 1 and Voyager 2. The Voyager program consists of a pair of unmanned scientific probes Voyager 1 and Galileo was an Unmanned spacecraft sent by NASA to study the Planet Jupiter and its moons Named after the Astronomer ^[3]

Discovery and naming

Amalthea was discovered on September 9, 1892 by Edward Emerson Barnard using the 36 inch (91 cm) refractor telescope at Lick Observatory. Events 1000 - Battle of Svolder, Viking Age. 1379 - Treaty of Neuberg, splitting the Austrian Year 1892 ( MDCCCXCII) was a Leap year starting on Friday (link will display the full calendar of the Gregorian Calendar (or a Leap year Edward Emerson Barnard ( December 16, 1857 – February 6, 1923) was an American Astronomer. The James Lick Telescope is an antique refracting 36 inch (91 The Lick Observatory is an astronomical Observatory, owned and operated by the University of California. It was the last planetary satellite to be discovered by direct visual observation (as opposed to photographically) and was the first new satellite of Jupiter since Galileo Galilei's discovery of the Galilean satellites in 1610. Galileo Galilei (15 February 1564 &ndash 8 January 1642 was a Tuscan ( Italian) Physicist, Mathematician, Astronomer, and Philosopher The Galilean moons are the four moons of Jupiter discovered by Galileo Galilei. ^[8]

The satellite is named after the nymph Amalthea from Greek mythology who nursed the infant Zeus (the Greek equivalent of Jupiter) with goat's milk. In Greek mythology, a nymph is any member of a large class of mythological entities in human female form In Greek mythology, Amalthea or Amaltheia ( Greek: Ἀμάλθεια is the most often mentioned among foster-mothers of Zeus. Greek mythology is the body of stories belonging to the ancient Greeks concerning their gods and Heroes the nature of the world and the origins and significance Zeus (zjuːs in Greek: nominative: Zeús /zdeús/ genitive: Diós; Modern Greek /'zefs/ in Greek mythology Milk is an opaque white liquid produced by the Mammary glands of female Mammals (including Monotremes. ^[8] Its Roman numeral designation is Jupiter V. Roman numerals are a Numeral system originating in ancient Rome, adapted from Etruscan numerals. The name "Amalthea" was not formally adopted by the IAU until 1975,^[11] although it had been in informal use for many decades. The name was initially suggested by Camille Flammarion^[12] Before 1975 Amalthea was most commonly known simply as Jupiter V. Nicolas Camille Flammarion ( February 26 1842 &ndash June 3 1925) was a French Astronomer and author The adjectival form of the name is Amalthean. ^[7]

Orbit

Amalthea circles Jupiter at a distance of 181,000 km (2. 54 Jupiter radii). The orbit of Amalthea has an eccentricity of 0. In Astrodynamics, under standard assumptions, any Orbit must be of Conic section shape 003 and an inclination of 0. Inclination in general is the Angle between a Reference plane and another plane or axis of direction 37° relative to the equator of Jupiter. ^[2] Such appreciably nonzero values of inclination and eccentricity, though still small, are unusual for an inner satellite and can be explained by the influence of the innermost Galilean satellite, Io: in the past Amalthea will have passed through several mean motion resonances with Io that will have excited its inclination and eccentricity (in a mean motion resonance the ratio of orbital periods of two bodies is a rational number like m:n). In Astronomy, an inner moon is a Natural satellite following a prograde, low inclination Orbit inwards of the large satellites of The Galilean moons are the four moons of Jupiter discovered by Galileo Galilei. TemplateInfobox Planet.--> Io (ˈaɪoʊ, or as Greek In Celestial mechanics, an orbital resonance occurs when two Orbiting bodies exert a regular periodic gravitational influence on each other usually due to their ^[9]

Amalthea's orbit lies near the outer edge of the Amalthea Gossamer Ring, which is composed of the dust ejected from the satellite. The planet Jupiter has a system of rings known as the rings of Jupiter or the Jovian ring system. ^[13]

Physical characteristics

The surface of Amalthea is very red (that is, its reflectivity increases with the wavelength from the green to near-infrared). Red is any of a number of similar Colors evoked by light consisting predominantly of the longest wavelengths of Light discernible by the human eye in the wavelength Infrared ( IR) radiation is Electromagnetic radiation whose Wavelength is longer than that of Visible light, but shorter than that of ^[3] The reddish color may be due to sulfur originating from Io or some other non ice material. Sulfur or sulphur (ˈsʌlfɚ see spelling below) is the Chemical element that has the Atomic number 16 TemplateInfobox Planet.--> Io (ˈaɪoʊ, or as Greek ^[3] Bright patches of green appear on the major slopes of Amalthea, but the nature of this color is currently unknown. Green is a Color, the perception of which is evoked by light having a spectrum dominated by energy with a Wavelength of roughly 520–570- nm. ^[3] The surface of Amalthea is slightly brighter than surfaces of other inner satellites of Jupiter. ^[5] There is also a substantial asymmetry between leading and trailing hemispheres: the leading hemisphere is 1. 3 times brighter than the trailing one. The asymmetry is probably caused by the higher velocity and frequency of impacts on the leading hemisphere, which excavate a bright material—presumably ice—from the interior of the moon. In the broadest sense the term impact crater can be applied to any depression natural or manmade resulting from the high velocity impact of a projectile with larger body ^[5]

Galileo images showing Amalthea's irregular shape

Amalthea is irregularly shaped, with the best ellipsoidal approximation being 250 × 146 × 128 km. Galileo was an Unmanned spacecraft sent by NASA to study the Planet Jupiter and its moons Named after the Astronomer An ellipsoid is a type of quadric surface that is a higher dimensional analogue of an Ellipse. ^[3] Like all other inner moons of Jupiter it is tidally locked with the planet, the long axis pointing towards Jupiter at all times. A separate article treats the phenomenon of Tidal resonance in Oceanography. ^[9] Its surface is heavily scarred by craters, some of which are extremely large relative to the size of the moon: Pan, the largest crater, measures 100 km across and is at least 8 km deep. In the broadest sense the term impact crater can be applied to any depression natural or manmade resulting from the high velocity impact of a projectile with larger body Pan is the largest crater on Jupiter 's moon Amalthea. It is 100 Kilometers across and at least 8 kilometers deep ^[3] Another crater, Gaea, measures 80 km across and is probably twice as deep as Pan. Gaea is an Impact crater on Amalthea, one of the small moons of Jupiter. ^[3] Amalthea has two prominent and named mountains, Mons Lyctas and Mons Ida with local relief reaching up to 20 km. Lyctos Facula is a Mountain on one of Jupiter 's smallest moons Amalthea. Ida Facula is a Mountain on Amalthea, one of Jupiter 's smallest moons ^[3]

Amalthea's irregular shape and large size led in the past to a conclusion that it is a fairly strong, rigid body,^[9] where it was argued that a body composed of ices or other weak materials would have been pulled into a more spherical shape by its own gravity. "Globose" redirects here See also Globose nucleus. A sphere (from Greek σφαίρα - sphaira, "globe However, on November 5, 2002, the Galileo orbiter made a targeted flyby that came within 160 km of Amalthea and the deflection of its orbit was used to compute the moon's mass (its volume had been calculated previously (to within 10% or so) from a careful analysis of all extant images). Events 1499 - Publication of the Catholicon in Treguier ( Brittany) See also 2002 (disambiguation Year 2002 ( MMII) was a Common year starting on Tuesday of the Gregorian calendar. Galileo was an Unmanned spacecraft sent by NASA to study the Planet Jupiter and its moons Named after the Astronomer ^[3] In the end, Amalthea's density was found to be as low as 0. 86 g/cm³,^[4][14] so it must be either a relatively icy body or very porous "rubble pile" or, more probably, something in between. In Astronomy, rubble pile is the informal name for an Asteroid that is not a Monolith, consisting instead of numerous pieces of rock that have coalesced Recent measurements from the Subaru telescope suggest that the moon is indeed icy,^[15] indicating that it cannot have formed in its current position, since the hot primordial Jupiter would have melted it. Subaru Telescope (In Japanese: すばる望遠鏡 is the 82 Metre flagship telescope of the National Astronomical Observatory of Japan, located in It is therefore likely to have formed farther from the planet or to be a captured Solar System body. The Solar System consists of the Sun and those celestial objects bound to it by Gravity. ^[4]

Amalthea radiates slightly more heat than it receives from the Sun, which is probably due to the influence of Jovian heat flux (<9° K), sunlight reflected from the planet (<5° K) and charged particle bombardment (<2° K). The Sun (Sol is the Star at the center of the Solar System. . ^[7] This is a trait shared with Io, although for very different reasons. TemplateInfobox Planet.--> Io (ˈaɪoʊ, or as Greek

Relationship with Jupiter's rings

Due to its low density and irregular shape, the escape velocity at the surface points of Amalthea closest to and furthest from Jupiter is no more than 1 m/s and dust can easily escape from it after e. In Physics, escape velocity is the speed where the Kinetic energy of an object is equal to the magnitude of its Gravitational potential energy g. micrometeorite impacts; this dust forms the Amalthea Gossamer Ring. The planet Jupiter has a system of rings known as the rings of Jupiter or the Jovian ring system. ^[9]

During its flyby of Amalthea, the Galileo orbiter's star scanner detected nine flashes which appear to be small moonlets near the orbit of Amalthea. Galileo was an Unmanned spacecraft sent by NASA to study the Planet Jupiter and its moons Named after the Astronomer Since they were sighted only from one location, their true distances couldn't be measured. The moonlets may be anywhere from gravel to stadium-sized. Their origins are unknown, but they may be gravitationally captured into current orbit or they may be ejecta from meteor impacts on the moon. See also Impact crater An impact event is the Collision of a large Meteoroid, Asteroid or Comet (generically On the next and final orbit, Galileo detected more of these moonlets. However, this time Amalthea was on the other side of the planet, so it is probable that the particles form a ring around the planet near Amalthea's orbit. A planetary ring is a ring of Cosmic dust and other small particles Orbiting around a Planet in a flat disc-shaped region ^[16]

Views to and from Amalthea

Computer simulation of Amalthea and Jupiter. The 'camera' is 1,000 km from Amalthea and the field of view is 26°. The field of view (also field of vision) is the angular extent of the observable world that is seen at any given moment

See also: Extraterrestrial skies

From Jupiter's surface —or rather, from just above its cloudtops— Amalthea would appear very bright, shining with a magnitude of −4. The ' Sky ' of a world refers to the view of the heavens from its surface The apparent magnitude ( m) of a celestial body is a measure of its Brightness as seen by an observer on Earth, normalized to the value 7,^[10] similar to that of Venus from Earth. The VENUS ( V ictoria E xperimental N etwork U nder the S ea project is a cabled sea floor observatory operated by the University At only 5 arcminutes across,^[17] its disc would be barely discernible and it would thus appear starlike. A minute of arc, arcminute, or MOA is a unit of angular measurement, equal to one sixtieth (1/60 of one degree. Amalthea's orbital period is only slightly longer than its parent planet's day (about 20% in this case), which means it would cross Jupiter's sky very slowly. The time between moonrise and moonset would be over 29 hours. ^[10]

From the surface of Amalthea, Jupiter would look enormous: 46 degrees across,^[17] it would appear roughly 92 times larger than the Full Moon. This article describes the unit of angle For other meanings see Degree. Full moon is a Lunar phase that occurs when the Moon is on the opposite side of the Earth from the Sun. Because Amalthea is in synchronous rotation, Jupiter would not appear to move, and would be invisible from one side of Amalthea. In Astronomy, synchronous rotation is a planetological term describing a body orbiting another where the orbiting body takes as long to rotate The Sun would disappear behind the planet's bulk for an hour and a half each revolution. Amalthea's short rotation period givesit just under six hours of daylight. Though Jupiter would appear 900 times brighter than the full Moon, its light would be spread over an area some 8500 times greater and it would not look as bright per surface unit. ^[10]

Exploration

In 1979–1980, the Voyager 1 and 2 spacecraft made the first images of Amalthea, which resolved its surface. The Voyager 1 spacecraft is a 722-kilogram robotic Space probe of the outer Solar system and beyond launched September 5, ^[3] They also measured the visible and infrared spectra and measured the moon's surface temperature. ^[7] Later, the Galileo orbiter completed the imaging of Amalthea's surface and a close flyby enabled it to constrain the moon's internal structure and composition. Galileo was an Unmanned spacecraft sent by NASA to study the Planet Jupiter and its moons Named after the Astronomer In 2006 Amalthea's orbit was refined by New Horizons spacecraft's instruments. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. New Horizons is a Robotic spacecraft mission by NASA currently underway

Named geological features

There are four named geological features on Amalthea: two craters and two faculae (bright spots),^[18] which are believed to be mountains. For the Genus of Gossamer-winged butterflies, see Facula (butterfly.

In fiction

Main article: Amalthea in fiction

Amalthea is the setting of several works of science fiction, including stories by Arthur C. Clarke and James Blish. Pan is the largest crater on Jupiter 's moon Amalthea. It is 100 Kilometers across and at least 8 kilometers deep Pan ( Greek, Genitive) is the Greek god of shepherds and flocks of mountain wilds hunting and rustic music paein means to pasture Gaea is an Impact crater on Amalthea, one of the small moons of Jupiter. Gaia (ˈgeɪə or /ˈgaɪə/ (" land " or " Earth " from the Ancient Greek Γαîα also Gæa or Gea Lyctos Facula is a Mountain on one of Jupiter 's smallest moons Amalthea. Crete ( Greek: Κρήτη transliteration: Krētē, modern transliteration Kriti) is the largest of the Greek islands and the Ida Facula is a Mountain on Amalthea, one of Jupiter 's smallest moons Two sacred mountains are called Mount Ida in Greek mythology, equally named "Mount of the Goddess Crete ( Greek: Κρήτη transliteration: Krētē, modern transliteration Kriti) is the largest of the Greek islands and the Jupiter 's extensive system of natural satellites &ndash in particular the four large Galilean moons (Io Europa Ganymede and Callisto &ndash has been a common Sir Arthur Charles Clarke, CBE (16 December 1917–19 March 2008 was a British Science fiction Author, Inventor, and James Benjamin Blish ( East Orange, New Jersey, May 23, 1921 – Henley-on-Thames, July 30, 1975) was an

References

External links

• Amalthea Profile by NASA's Solar System Exploration
• Another find for Galileo – Galileo Millennium Mission status report (2003-04-09)
• Jupiter's Amalthea Surprisingly Jumbled – JPL press release (2002-12-09)
• Jupiter From Amalthea, a painting by Frank Hettick, 2002. Year 2003 ( MMIII) was a Common year starting on Wednesday of the Gregorian calendar. Events 193 - Septimius Severus is proclaimed Roman Emperor by the army in Illyricum (in the Balkans) See also 2002 (disambiguation Year 2002 ( MMII) was a Common year starting on Tuesday of the Gregorian calendar. Events 536 - Byzantine General Belisarius enters Rome while the Ostrogothic garrison peacefully leaves the city