Ganymede is the largest moon of Jupiter, but also the solar system. It is bigger than Mercury, but with roughly half the mass of Mercury. It was discovered in 1610 by Galileo Galilei and Simon Marius, who named it in honor of Ganymede, the Trojan prince of great beauty, abducted by Zeus, the eagle, while he was tending his flock on Mount Ida in Troas.
Ganymede is composed of silicate and water ice based on a liquid mantle could contain liquid water. In 1972, a team of astronomers detected a thin atmosphere around Ganymede during an eclipse, from a tenuous atmosphere of oxygen, very similar to that of Europe, was confirmed by the Hubble Space Telescope.
The Galileo spacecraft orbiting Jupiter in 2000, was able to zoom in Ganymede. The dark regions on Ganymede are heavily cratered, implying they are very old, while the light regions are younger and dotted grooves. The crater on Ganymede CHRYSOR extends approximately 6000 meters and the crater on Aleyna 12 000 meters. Like our own moon, Ganymede rotates synchronously and always presents the same face toward the planet Jupiter.
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|Ganymede|| ||Moon of Jupiter|
|Diameter|| ||5 262 km|
|Mass|| ||1,5×1023 kg|
|Temperature|| ||156 k|
|Discovery date || ||1610|
|Discovered by|| ||G. Galilei et Simon Marius|
|Semi-major axis|| ||1 070 400 km|
|Apoapsis|| ||1 071 600 km|
|Periapsis|| ||1 069 200 km|
|Orbital period|| ||7, 155 days|
Image: Ganymede has a shiny surface speckled with craters. In this detailed mosaic taken by the Galileo spacecraft around Jupiter from 1995 to 2003, the colors of the moon were very different. Credit: Galileo Project, DLR, JPL, NASA
This moon is visible at the bottom right of the photo is Ganymede, and the planet Jupiter, seems the monitor. The search for extraterrestrial life in our own solar system looks at Ganymede who might have liquid oceans under the surface.
She is one of the moons, Europa and Callisto as seas where liquid water may be present in the surface layers of ice.
The hypothesis of the ocean was seen as an explanation for the unusually strong magnetic field of Ganymede.
Ganymede, the largest moon in the solar system, also has the largest measured magnetic field of all the moons.
Exobiologists Some speculate that life may be able to emerge in such an ocean, just as in ancient oceans of the Earth. As the moon Ganymede keeps the same face toward its central planet, Jupiter.
If Ganymede was in orbit around the Sun, it would be considered a planet because it is larger than the planet Mercury. In 1999, a debris disk in the form of ring was detected as for Europe and Callisto.
Galileo spacecraft that orbited Jupiter from December 1995 to September 2003 was also observed Ganymede.
That Galileo has provided evidence of the existence of a magnetic field, a thin atmosphere and a layer of water below the surface.
Ganymede will again be revisited during the space mission Europa Jupiter System Mission, planned in the 2020s.
Image: Credit: Cassini Imaging Team, Cassini Project, NASA
Jupiter, the largest planet in our solar system is surrounded by more than 60 moons.
The moons of Jupiter were first discovered in 1610. Galileo Galilei discovered at that time the four largest Jovian satellites system Io, Europa, Ganymede and Callisto.
These Galilean moons called for, were the first to be observed except that of Earth. Today, thanks to space probes, we have a more comprehensive view of the Jovian system. This is the series of Voyager missions which helped lift the veil on the Jovian system by discovering in 1979, Metis, and Thebe Adrastea.
Before the space age, astronomers have discovered Amalthea (1892), Himalia (1904), Elara (1905), Pasiphae (1908), Sinope (1914), and Lysithea Carme (1938), Ananke (1951), Leda (1974 ) and Themisto (1975. Between 1979 and 1999, no new satellite of Jupiter was not discovered and it was not until October 6, 1999, for the Spacewatch program discovers a new moon to Jupiter, Callirrhoe.
Observations in 2000 revealed ten new moons, bringing the number of satellites to 28 after the rediscovery of Themisto, Kalyke, Iocasta, Erinome, Harpalyke, Isonoe, Praxidike, Megaclite, Taygete, Chaldene and S/2000 J 11.
The following year, eleven other moons were discovered, bringing the total to 39, Hermippe, Eurydome, Sponde, Kale, Autonoe, Thyone, Pasithee, Euanthe, Orthosie, Europie, Aitne.
In 2002, only one moon, Arche, was discovered.
In 2003 there discovered 23 new satellites, Eukelade, S/2003 J 2, S/2003 J 3, S/2003 J 4, S/2003 J 5, Helice, Aoede, hegemone, S/2003 J 9, S / 2003 J 10, Kallichore, S/2003 J 12, Cyllene, S/2003 J 14 S/2003 J 15 S/2003 J 16 S/2003 J 17 S/2003 J 18 S/2003 J 19 , Carpo, Mneme, Thelxinoe and S/2003 J 23. Most of the 47 satellites discovered after the 2000s are small moons of a few kilometers in diameter, the largest accounting for just 9 km. In 2006, 63 were known moons of Jupiter, the record of the solar system.
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|Ganymede||5262 km||1,5×1023 kg|
|Callisto||4821 km||1,1×1023 kg|
|Io ||3643 km||8,9x1022 kg|
|Europa||3122 km||4,8×1022 kg|
|Amalthea||262x146x134 km||2,1x1018 kg|
|Himalia||170 km||6,7×1018 kg|
|Thebe||110x90 km||1,5x1018 kg|
|Elara||86 km||8,7×1017 kg|
|Pasiphaë||60 km||3,0×1017 kg|
|Carme||46 km||1,3×1017 kg|
|Sinope||38 km||7,5×1016 kg|
|Lysithea||36 km||6,3×1016 kg|
|Ananke||28 km||3,0×1016 kg|
|Leda||20 km||1,1×1016 kg|