Ganymede
Satellite of Jupiter
John Lazarz
Earth 450
April 29, 2013
Radius (km)
Normalized to
Earth
Jupiter
69,911
10.97
Saturn
58,232
9.14
Uranus
25,362
3.98
Neptune
24,622
3.86
Earth
6,371
1.00
Venus
6,052
0.95
Mars
3,390
0.53
2,631
0.41
2,440
0.38
Callisto
2,410
0.38
Io
1,821
0.29
1,737
0.27
1,561
0.25
1,153
0.18
Ganymede
Mercury
Moon
Europa
Pluto
http://www.universetoday.com/wp-content/uploads/2008/07/787px-moons_of_solar_system.jpg
Orbit Radius Around Jupiter
1,070,400 km
Orbit time
7.15455296 Earth days
Orbit Circumference
6,725,518.71 km
Average Orbit Velocity
39,165.6 km/h
Orbit Eccentricity
0.0013
Mean Radius
2,631.2 km
Volume
76,304,506,998 km3
Mass
1.4819 x 1023 kg
Density
1.942 g/cm3
Surface Area
86,999,665.93 km2
Surface Gravity
1.428 m/s2
Escape Velocity
2.74 km/s
Surface Temperature
70-152 K
http://solarsystem.nasa.gov/planets/profile.cfm?Object=Jup_Ganymede&Display=Facts
Discovery
• Galileo Galile
– 1/ 7/ 1610
• Pioneer
– 3/12/1973
• Voyager
– 7/9/1979
• Galileo
– 6/27/1996
http://solarsystem.nasa.gov/planets/profile.cfm?Object=Jup_Ganymede
Pioneer 10,11
• Arrived 1973
• Sent back limited data
and blurry images
• Determined mass ratios
of Galilean satellites to
Jupiter via Doppler
measurements
(Null, 1976)
http://en.wikipedia.org/wiki/File:Pioneer_10_-_Ganymede_-_P102a.jpg
Galileo
• Arrived 1996
• High-Resolution
Imaging
• Gravity Measurements
http://www.mmedia.is/~bjj/povstuff/spacecraft/
Enki Catena Crater Chain
• 13 craters
• Comet pulled into
pieces by Jupiter
• 214 km x 217 km
http://photojournal.jpl.nasa.gov/catalog/PIA01610
Mass Anomalies
http://www.jpl.nasa.gov/news/news.php?release=2004-200
Mass Anomalies
(Palguta et al., 2006)
Galileo Images
Uruk Sulcus
Voyager Images
http://solarsystem.dlr.de/Missions/galileo/Presse/GLL_press/1997/p48112_full.jpg
Older: PLT1, PLT2, PLT3
(Pitted and lineated Terrain)
Intermediate: PMRT1,
PMRT2, PMRT3
(Parallel Mesa and Ridged
Terrain)
Braided Terrain (BT)
Striated Terrain (ST)
Cuspate Ridged Terrain (CRT)
Younger: CRT1, CRT2
Parallel Ridged Terrain (PRT)
Parallel Ridged Terrain in
Spindle-Shaped Occurrence
(PRTS)
En Echelon Ridged Terrain
(EERT)
(Pappalardo et al., 1998)
Possible fault geometry in lanes of parallel ridged terrain. Voyager-scale blocks may be
associated with extensional necking of the lithosphere, and large scale shear zones (half
arrows) are envisioned as reaching to the brittle-ductile transition (dashed).
(Pappalardo et al., 1998)
Magnetic Field
• Field tilted by 10˚
relative to spin axis
• Surface-field of 750 nT
– Earth ~31 µT
(Kivelson et al., 1996)
Structure
•
Before Galileo:
– 60% rock
– 40% ice
•
Galileo:
– Metallic core
400-1,300 km
– Silicate mantle
– Ice shell 800 km thick
•
Any Point on the surface defines a
possible model for Ganymede’s
internal mass distribution
– A. Core density of 5150 kg/m3 FeFeS
– B. Core density of 8000 kg/m3 Fe
(Anderson et al., 1996)
Hubble
• Detected ozone on the
trailing hemisphere.
• Possibly produced by
ions impacting water
molecules beneath the
ice surface.
• Small amount of ozone:
1-10% of the amount of
ozone destroyed each
winter on Earth
http://hubblesite.org/newscenter/archive/releases/1995/36/image/a/
(Noll et al., 1996)
New Horizons
• Arrived 2007
• Topography and
composition maps
• Looking at surface
composition of
Ganymede Jupiter
facing hemisphere.
http://photojournal.jpl.nasa.gov/catalog/PIA09239
Io
Ganymede
References
Null G. W., (1976) Gravity field of Jupiter and its satellites from Pioneer 10 and
Pioneer 11 tracking data, The Astronomical Journal 81, 1153-1161
Paulguta J. et al., (2006) Mass anomalies on Ganymede, Icarus 180, 428-441
Papalardo R.T. et al., (1998) Grooved terrain on Ganymede: first results from
Galileo high-resolution imaging, Icarus 135, 276-302
Kivelson M.G. et al., (1996) Discovery of Ganymede’s magnetic field by the
Galileo spacecraft, Nature 384, 537-541
Anderson J.D. et al., (1996) Gravitational constraints on internal structure of
Ganymede, Nature 384, 541-543
Noll K.S. et al., (1996) Detection of ozone on Ganymede, Science 273, 341-343