Ganymede (moon)

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True color image taken by the Galileo probe
Click image for description
Discovered by G. Galilei
S. Marius
Discovery time January 11, 1610
Shortest distance from what it orbits around 1,069,200 km (0.007147 AU)
Longest distance from what it orbits around 1,071,600 km (0.007163 AU)
Avgdistance from the center of its orbital path 1,070,400 km (0.007155 AU)
How egg-shaped its orbit is
How long it takes to complete an orbit 7.15455296 d (0.019588 a)
Average speed 10.880 km/s
Angle above the reference plane
2.21° (to the ecliptic)
0.20° (to Jupiter's equator)
What it orbits Jupiter
Size and Other Qualities
Average distance from its center to its surface 2631.2 km (0.413 Earths)
Area of its surface 87.0 million km² (0.171 Earths) [2]
Volume inside it 7.6×1010 km³ (0.0704 Earths)
Mass 1.4819×1023 kg (0.025 Earths)
Average density 1.942 g/cm³
Gravity at its surface 1.428 m/s2 (0.146 g)
Slowest speed able to escape into space
("escape velocity")
2.741 km/s (6,130 mph)
How long it takes to turn around one time synchronous
Angle at which it turns
(in relation to its orbit)
How much light it reflects 0.43 ± 0.02[3]
Avg. surface temp. ~109 K (−172 °C)
Seeming brightness
("apparent magnitude")
4.61 (opposition) [3]
Pressure trace
Make up oxygen

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 | change source]

  1. "Ganymede: Facts and Figures". Solar System Exploration. 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. 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. Retrieved 2007-11-24.

Other Websites[change | change source]