Play Video
1
Amalthea - The Sad Smile of The Moon
Amalthea - The Sad Smile of The Moon
::2011/01/15::
Play Video
2
Amalthea - Moon for Sale -- Lunar Property |Lunar Embassy
Amalthea - Moon for Sale -- Lunar Property |Lunar Embassy
::2010/12/12::
Play Video
3
Jupiter
Jupiter's Moon: Amalthea Rotation
::2010/01/06::
Play Video
4
Jupiter Moon - Amalthea - Real Pictures - youtube.com/MoonsMonde
Jupiter Moon - Amalthea - Real Pictures - youtube.com/MoonsMonde
::2013/10/07::
Play Video
5
Amalthea(spa) The Sad Smile of the Moon. demo Immortal Autumn 1997
Amalthea(spa) The Sad Smile of the Moon. demo Immortal Autumn 1997
::2011/02/03::
Play Video
6
Sarkophagus - Amalthea
Sarkophagus - Amalthea
::2012/11/25::
Play Video
7
Moon 9th September, 2012 (Amalthea mix)
Moon 9th September, 2012 (Amalthea mix)
::2012/09/09::
Play Video
8
Amalthea (Unicorn) & Derek - /\ Non/Disney Crossover /\ Over and Over
Amalthea (Unicorn) & Derek - /\ Non/Disney Crossover /\ Over and Over
::2009/09/24::
Play Video
9
Kaimo K - Amalthea
Kaimo K - Amalthea
::2013/04/15::
Play Video
10
Flight around Amalthea
Flight around Amalthea
::2009/05/13::
Play Video
11
John Hill - Amalthea
John Hill - Amalthea
::2012/02/23::
Play Video
12
My Heart Will go on {Amalthea X Helios}
My Heart Will go on {Amalthea X Helios}
::2013/03/11::
Play Video
13
Amalthea - Harm [Official]
Amalthea - Harm [Official]
::2014/05/18::
Play Video
14
Zooming Out From Jupiter Showing Moon Orbits [720p]
Zooming Out From Jupiter Showing Moon Orbits [720p]
::2009/09/22::
Play Video
15
Amalthea - Vapour
Amalthea - Vapour
::2014/02/06::
Play Video
16
Jim Hawkins and Amalthea: The Voice
Jim Hawkins and Amalthea: The Voice
::2009/08/02::
Play Video
17
Amalthea Trailer
Amalthea Trailer
::2011/07/01::
Play Video
18
Amalthea and Lir. I never had a Dream come True
Amalthea and Lir. I never had a Dream come True
::2007/07/06::
Play Video
19
Amazing Moons of Jupiter with Dr. Alan Stern
Amazing Moons of Jupiter with Dr. Alan Stern
::2009/08/31::
Play Video
20
Non/Disney Crossover - Dream fortress [ Amalthea/Maleficent ]
Non/Disney Crossover - Dream fortress [ Amalthea/Maleficent ]
::2014/08/13::
Play Video
21
If Amalthea Cared
If Amalthea Cared
::2007/10/04::
Play Video
22
Phases of Jupiter
Phases of Jupiter
::2011/07/08::
Play Video
23
The Natural Satellites (Moon) Song - Hope Johnson
The Natural Satellites (Moon) Song - Hope Johnson
::2013/04/01::
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24
Amalthea
Amalthea
::2014/09/20::
Play Video
25
Teach Astronomy - Moons of Jupiter
Teach Astronomy - Moons of Jupiter
::2010/07/08::
Play Video
26
Last Unicorn - Amalthea
Last Unicorn - Amalthea's Eyes
::2010/02/28::
Play Video
27
A REPORT ON AMALTHEA
A REPORT ON AMALTHEA
::2007/10/25::
Play Video
28
Amalthea - Trachea
Amalthea - Trachea
::2011/05/05::
Play Video
29
Amalthea - Awake Wither
Amalthea - Awake Wither
::2013/04/23::
Play Video
30
Amalthea - Vapor
Amalthea - Vapor
::2011/09/16::
Play Video
31
Amalthea(spa) Ethereal Sky. demo Immortal Autumn 1997
Amalthea(spa) Ethereal Sky. demo Immortal Autumn 1997
::2011/02/03::
Play Video
32
The Last Unicorn: Fate: Amalthea and Lir
The Last Unicorn: Fate: Amalthea and Lir
::2008/12/06::
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33
Amalthea - The King Takes the Queen - Cry Me a River 2006
Amalthea - The King Takes the Queen - Cry Me a River 2006
::2007/01/22::
Play Video
34
Lady Amalthea: Not The Same
Lady Amalthea: Not The Same
::2010/07/06::
Play Video
35
AMALTHEA
AMALTHEA'12 Promo
::2012/10/04::
Play Video
36
Amalthea - We Smile in Denial
Amalthea - We Smile in Denial
::2012/04/08::
Play Video
37
Amalthea(spa) Misty Faces. demo Immortal Autumn 1997
Amalthea(spa) Misty Faces. demo Immortal Autumn 1997
::2011/02/03::
Play Video
38
How to Pronounce Amalthea
How to Pronounce Amalthea
::2013/05/23::
Play Video
39
Canalturf TV - Vendredi 28 mars 2014 - PRIX RMC - PRIX AMALTHEA - PARIS-VINCENNES - Quinté+ PMU
Canalturf TV - Vendredi 28 mars 2014 - PRIX RMC - PRIX AMALTHEA - PARIS-VINCENNES - Quinté+ PMU
::2014/03/26::
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40
GROUNDCOVER. "Amalthea,io" 【YEALO! vol.28】Archive-05
GROUNDCOVER. "Amalthea,io" 【YEALO! vol.28】Archive-05
::2013/07/08::
Play Video
41
The Last Unicorn - Now That I
The Last Unicorn - Now That I'm A Woman [High Quality]
::2007/06/10::
Play Video
42
Amalthea - AWCISM - Cry Me a River 2006
Amalthea - AWCISM - Cry Me a River 2006
::2007/01/16::
Play Video
43
Amalthea - End @ Henriksberg, Ballroom 20140131 [LIVE]
Amalthea - End @ Henriksberg, Ballroom 20140131 [LIVE]
::2014/02/03::
Play Video
44
Chief Scientist and Research Director, NASA: Dr. Kamlesh Lulla @ Amalthea 2013, IIT Gn
Chief Scientist and Research Director, NASA: Dr. Kamlesh Lulla @ Amalthea 2013, IIT Gn
::2013/10/06::
Play Video
45
AMALTHEA
AMALTHEA'11 promo
::2011/10/06::
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46
Amalthea ~BORDERLINE~ Audition
Amalthea ~BORDERLINE~ Audition
::2011/05/30::
Play Video
47
The Moon and Jupiter and its 4 moons recorded with a video camera.
The Moon and Jupiter and its 4 moons recorded with a video camera.
::2011/09/20::
Play Video
48
Melody-Sailor Moon
Melody-Sailor Moon
::2009/03/29::
Play Video
49
Bring Me That Horizon by Amalthea
Bring Me That Horizon by Amalthea
::2009/01/12::
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50
AMALTHEA CELLARS ASTOUNDS EXPERTS AT WINETASTING COMPETITION
AMALTHEA CELLARS ASTOUNDS EXPERTS AT WINETASTING COMPETITION
::2008/06/20::
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RESULTS [51 .. 101]
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Amalthea
Amalthea PIA02532.png
Greyscale Galileo images of Amalthea
Discovery
Discovered by E.E. Barnard
Discovery date September 9, 1892
Designations
Adjectives Amalthean
Orbital characteristics
Periapsis 181150 km[a]
Apoapsis 182840 km[a]
Mean orbit radius
181365.84±0.02 km (2.54 RJ)[1]
Eccentricity 0.00319±0.00004[1]
0.49817943±0.00000007 d (11 h, 57 min, 23 s)[1]
26.57 km/s[a]
Inclination 0.374°±0.002° (to Jupiter's equator)[1]
Satellite of Jupiter
Physical characteristics
Dimensions 250 × 146 × 128 km[2]
Mean radius
83.5±2.0 km[2]
Volume (2.43±0.22)×106 km3[3]
Mass (2.08±0.15)×1018 kg[3]
Mean density
0.857±0.099 g/cm³[3]
≈ 0.020 m/s² (≈ 0.002 g)[a]
≈ 0.058 km/s[a]
synchronous[2]
zero[2]
Albedo 0.090±0.005[4]
Surface temp. min mean max
[6] 120 K 165 K
14.1[5]

Amalthea (/æməlˈθə/ am-əl-THEE; Greek: Αμάλθεια) is the third moon of Jupiter in order of distance from the planet. It was discovered on September 9, 1892, by Edward Emerson Barnard and named after Amalthea, a nymph in Greek mythology.[7] 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.[8] From its surface, Jupiter would be an astonishing sight in its sky, appearing 46.5 degrees in diameter.[b] Amalthea is the largest of the inner satellites of Jupiter. Irregularly shaped and reddish in color, it is thought to consist of porous water ice with unknown amounts of other materials. Its surface features include large craters and ridges.[2]

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.[2]

Discovery and naming[edit]

Voyager 1 color image of Amalthea (1979)

Amalthea was discovered on September 9, 1892, by Edward Emerson Barnard using the 36 inch (91 cm) refractor telescope at Lick Observatory.[7] 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.[9]

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.[10] Its Roman numeral designation is Jupiter V. The name "Amalthea" was not formally adopted by the IAU until 1976,[11][12] although it had been in informal use for many decades. The name was initially suggested by Camille Flammarion.[13] Before 1976 Amalthea was most commonly known simply as Jupiter V. The adjectival form of the name is Amalthean.[6]

Orbit[edit]

Amalthea circles Jupiter at a distance of 181 000 km (2.54 Jupiter radii). The orbit of Amalthea has an eccentricity of 0.003 and an inclination of 0.37° relative to the equator of Jupiter.[1] 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 has passed through several mean motion resonances with Io that 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).[8]

Amalthea's orbit lies near the outer edge of the Amalthea Gossamer Ring, which is composed of the dust ejected from the satellite.[14]

Physical characteristics[edit]

The surface of Amalthea is very red (that is, its reflectivity increases with the wavelength from the green to near-infrared).[2] The reddish color may be due to sulfur originating from Io or some other non-ice material.[2] Bright patches of less red tint appear on the major slopes of Amalthea, but the nature of this color is currently unknown.[2] The surface of Amalthea is slightly brighter than surfaces of other inner satellites of Jupiter.[4] 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.[4]

Galileo images showing Amalthea's irregular shape
The most detailed existing image of Amalthea (2.4 km/pix).[8] Anti-Jupiter side. Ida Facula and Lyctos Facula are on the left side (on the terminator). Bright spot underside is associated with crater Gaea. Photo by Galileo (2000)

Amalthea is irregularly shaped, with the best ellipsoidal approximation being 250 × 146 × 128 km.[2] From this, Amalthea's surface area is likely between 88,000 and 170,000 square kilometers, or somewhere near 130,000. Like all other inner moons of Jupiter it is tidally locked with the planet, the long axis pointing towards Jupiter at all times.[8] 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.[2] Another crater, Gaea, measures 80 km across and is likely twice as deep as Pan.[2] Amalthea has several prominent bright spots, two of which are named. They are Lyctos Facula and Ida Facula, with width reaching up to 25 km. They are located on the edge of ridges.[2]

Amalthea's irregular shape and large size led in the past to a conclusion that it is a fairly strong, rigid body,[8] 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. 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).[2] In the end, Amalthea's density was found to be as low as 0.86 g/cm³,[3][15] so it must be either a relatively icy body or very porous "rubble pile" or, more likely, something in between. Recent measurements of infrared spectra from the Subaru telescope suggest that the moon indeed contains hydrous minerals (or organic materials), indicating that it cannot have formed in its current position, since the hot primordial Jupiter would have melted it.[16] It is therefore likely to have formed farther from the planet or to be a captured Solar System body.[3] Unfortunately, no images were taken during this flyby (Galileo's cameras had been deactivated due to radiation damage in January 2002), and the resolution of other available images is generally low.

Amalthea radiates slightly more heat than it receives from the Sun, which is probably due to the influence of Jovian heat flux (<9 kelvin), sunlight reflected from the planet (<5 K), and charged particle bombardment (<2 K).[6] This is a trait shared with Io, although for very different reasons.

Relationship with Jupiter's rings[edit]

Due to tidal force from Jupiter and Amalthea's low density and irregular shape, the escape velocity at it's surface points closest to and furthest from Jupiter is no more than 1 m/s and dust can easily escape from it after, e.g. micrometeorite impacts; this dust forms the Amalthea Gossamer Ring.[8]

During its flyby of Amalthea, the Galileo orbiter's star scanner detected nine flashes that appear to be small moonlets near the orbit of Amalthea. Since they were sighted only from one location, their true distances could not be measured. These moonlets may be anywhere in size 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 Amalthea. On the next and final orbit (just an hour before destruction), Galileo detected one more such moonlet. 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.[17][18][19][20]

Views to and from Amalthea[edit]

From Jupiter's surface—or rather, from just above its cloudtops—Amalthea would appear very bright, shining with a magnitude of −4.7,[b] similar to that of Venus from Earth. At only 8 arcminutes across,[c] its disc would be barely discernible. 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.[b]

From the surface of Amalthea, Jupiter would look enormous: 46 degrees across,[c] it would appear roughly 92 times larger than the full moon. Because Amalthea is in synchronous rotation, Jupiter would not appear to move, and would not be visible from one side of Amalthea. The Sun would disappear behind Jupiter's bulk for an hour and a half each revolution, and Amalthea's short rotation period gives it 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.[b]

Exploration[edit]

In 1979–1980, the unmanned Voyager 1 and Voyager 2 spaceprobes made the first images of Amalthea, which resolved its surface.[2] They also measured the visible and infrared spectra and surface temperature.[6] Later, the Galileo orbiter completed the imaging of Amalthea's surface. Amalthea provided the final satellite fly-by for Galileo on November 5, 2002, at a distance from the moon's center of approximately 244 km (152 mi) (height about 160–170 km), permitting the moon's mass to be accurately determined, while changing Galileo's trajectory so that it would plunge into Jupiter in September 2003, having finished its mission.[3] In 2006 Amalthea's orbit was refined by New Horizons spacecraft's instruments.

Named geological features[edit]

Leading side of Amalthea. North is up, and Jupiter is beyond the right side. Crater Pan is seen on the upper right edge, and Gaea on the lower. Ida Facula and Lyctos Facula are on the left end (upper and lower brightenings respectively)

There are four named geological features on Amalthea: two craters and two faculae (bright spots).[21] The faculae are located on the edge of a ridge on the anti-Jupiter side of Amalthea.[2]

Feature Named after
Pan (crater) Pan, Greek god
Gaea (crater) Gaia, Greek goddess
Lyctos Facula Lyctus, Crete
Ida Facula Mount Ida, Crete

In fiction[edit]

Main article: Amalthea in fiction

Amalthea is the setting of several works of science fiction, including stories by Arthur C. Clarke and James Blish.

Notes[edit]

  1. ^ a b c d e Calculated on the basis of other parameters.
  2. ^ a b c d Calculated on the basis of known distances, sizes, periods and visual magnitudes as visible from the Earth. Visual magnitudes as seen from Jupiter mj are calculated from visual magnitudes on Earth mv using the formula mj=mv−log2.512(Ij/Iv), where Ij and Iv are respective brightnesses (see visual magnitude), which scale according to the inverse square law. For visual magnitudes see http://www.oarval.org/ClasSaten.htm and Jupiter (planet).
  3. ^ a b Calculated from the known sizes and distances of the bodies, using the formula 2*arcsin(Rb/Ro), where Rb is the radius of the body and Ro is the radius of Amalthea's orbit or distance from the Jovian surface to Amalthea.

References[edit]

  1. ^ a b c d e Cooper Murray et al. 2006.
  2. ^ a b c d e f g h i j k l m n o p Thomas Burns et al. 1998.
  3. ^ a b c d e f Anderson Johnson et al. 2005.
  4. ^ a b c Simonelli Rossier et al. 2000.
  5. ^ Observatorio ARVAL.
  6. ^ a b c d Simonelli 1983.
  7. ^ a b Barnard 1892.
  8. ^ a b c d e f Burns Simonelli et al. 2004.
  9. ^ Bakich M. E. (2000). The Cambridge Planetary Handbook. Cambridge University Press. pp. 220–221. ISBN 9780521632805. 
  10. ^ "Planet and Satellite Names and Discoverers". Gazetteer of Planetary Nomenclature. International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN). Archived from the original on 2014-08-21. Retrieved 2014-10-08. 
  11. ^ Blunck J. (2010). Solar System Moons: Discovery and Mythology. Springer. pp. 9–15. Bibcode:2010ssm..book.....B. doi:10.1007/978-3-540-68853-2. ISBN 978-3-540-68852-5. 
  12. ^ Flammarion C., Kowal C., Blunck J. (1975-10-07). "Satellites of Jupiter". International Astronomical Union Circular 2846. Central Bureau for Astronomical Telegrams. Archived from the original on 2014-02-22. Retrieved 2014-10-17.  (Bibcode1975IAUC.2846....6F)
  13. ^ Flammarion 1893.
  14. ^ Burns Showalter et al. 1999.
  15. ^ Swiss Cheese Moon.
  16. ^ Takato Bus et al. 2004.
  17. ^ Fieseler P. D., Adams O. W., Vandermey N., Theilig E. E., Schimmels K. A., Lewis G. D., Ardalan S. M., Alexander C. J. (2004). "The Galileo star scanner observations at Amalthea". Icarus 169 (2): 390–401. Bibcode:2004Icar..169..390F. doi:10.1016/j.icarus.2004.01.012. 
  18. ^ "Another Find for Galileo". Jet Propulsion Laboratory. 9 April 2003. Archived from the original on 2004-11-04. Retrieved 2012-03-27. 
  19. ^ Fieseler P. D., Ardalan S. M. (2003-04-04). "Objects near Jupiter V (Amalthea)". International Astronomical Union Circular 8107. Central Bureau for Astronomical Telegrams. Archived from the original on 2014-03-02. Retrieved 2014-10-12.  (Bibcode2003IAUC.8107....2F)
  20. ^ Emily Lakdawalla (2013-05-17). "A serendipitous observation of tiny rocks in Jupiter's orbit by Galileo". The Planetary Society. Archived from the original on 2014-08-14. Retrieved 2014-10-14. 
  21. ^ USGS: Jupiter: Amalthea.

Cited sources

External links[edit]

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