Ganymede (moon)

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Ganymede
True color image taken by the Galileo probe
Click image for description
Discovery
Discovered by G. Galilei
S. Marius
Discovery date January 11, 1610
Orbital characteristics
Periapsis 1,069,200 km (0.007147 AU)
Apoapsis 1,071,600 km (0.007163 AU)
Mean orbit radius 1,070,400 km (0.007155 AU)
Eccentricity 0.002[1]
Orbital period 7.15455296 d (0.019588 a)
Average orbital speed 10.880 km/s
Inclination 2.21° (to the ecliptic)
0.20° (to Jupiter's equator)
Satellite of Jupiter
Physical characteristics
Mean radius 2631.2 km (0.413 Earths)
Surface area 87.0 million km² (0.171 Earths) [2]
Volume 7.6×1010 km³ (0.0704 Earths)
Mass 1.4819×1023 kg (0.025 Earths)
Mean density 1.942 g/cm³
Equatorial surface gravity 1.428 m/s2 (0.146 g)
Escape velocity 2.741 km/s (6,130 mph)
Rotation period synchronous
Axial tilt zero

Ganymede is the largest moon of Jupiter. It is also the largest moon in the Solar System. Ganymede is larger in diameter than Mercury, but has only about half its mass. Ganymede is much less dense. Ganymede is part of a group called the Galilean Satellites. These also include Io, Europa and Callisto.

Galileo Galilei discovered this moon in 1610.[4] Simon Marius suggested the name Ganymede soon after. In Greek mythology, Ganymede was Zeus' cup-bearer.[5] This name and the names of the other Galilean satellites were not favoured for a long time, and were not put into common use until the mid-20th century. Instead, it is simply referred to by its Roman numeral designation (a system that was introduced by Galileo) as Jupiter III or as the "third satellite of Jupiter".[6] Ganymede is the only Galilean moon of Jupiter named after a male figure.

References[change]

  1. "Ganymede: Facts and Figures". Solar System Exploration. http://solarsystem.nasa.gov/planets/profile.cfm?Object=Jup_Ganymede&Display=Facts&System=Metric. Retrieved 2007-12-07.
  2. Using the mean radius
  3. 3.0 3.1 Yeomans, Donald K. (2006-Jul-13). "Planetary Satellite Physical Parameters". JPL Solar System Dynamics. http://ssd.jpl.nasa.gov/?sat_phys_par. Retrieved 2007-11-05.
  4. Galilei, G.; Sidereus Nuncius (March 13, 1610)
  5. Marius, S.; (1614); Mundus Iovialis anno M.DC.IX Detectus Ope Perspicilli Belgici [1], where he attributes the suggestion to Johannes Kepler
  6. "Satellites of Jupiter". The Galileo Project. http://galileo.rice.edu/sci/observations/jupiter_satellites.html. Retrieved 2007-11-24.

Other Websites[change]