Media Information

 
 
 
Collection:
NASA Planetary Photo Journal Collection
Title:
Ganymede G1 & G2 Encounters - Interior of Ganymede
Original Caption Released with Image:
Voyager images are used to create a global view of Ganymede. The cut-out reveals the interior structure of this icy moon. This structure consists of four layers based on measurements of Ganymede's gravity field and theoretical analyses using Ganymede's known mass, size and density. Ganymede's surface is rich in water ice and Voyager and Galileo images show features which are evidence of geological and tectonic disruption of the surface in the past. As with the Earth, these geological features reflect forces and processes deep within Ganymede's interior. Based on geochemical and geophysical models, scientists expected Ganymede's interior to either consist of: a) an undifferentiated mixture of rock and ice or b) a differentiated structure with a large lunar sized "core" of rock and possibly iron overlain by a deep layer of warm soft ice capped by a thin cold rigid ice crust. Galileo's measurement of Ganymede's gravity field during its first and second encounters with the huge moon have basically confirmed the differentiated model and allowed scientists to estimate the size of these layers more accurately. In addition the data strongly suggest that a dense metallic core exists at the center of the rock core. This metallic core suggests a greater degree of heating at sometime in Ganymede's past than had been proposed before and may be the source of Ganymede's magnetic field discovered by Galileo's space physics experiments.

Galileo's primary 24 month mission includes eleven orbits around Jupiter and will provide observations of Jupiter, its moons and its magnetosphere. The Galileo mission is managed by the Jet Propulsion Laboratory for NASA's Office of Space Science, Washington, D.C.

This image and other images and data received from Galileo are posted on the Galileo mission home page on the World Wide Web at http://galileo.jpl.n asa.gov.
Addition Date:
1997-12-16
Produced By:
JPL
Mission:
Galileo
Spacecraft:
Galileo Orbiter
Target Name:
Ganymede
Is a satellite of:
Jupiter
Product Size:
2667 samples x 2000 lines
Primary Data Set:
Galileo EDRs
Producer ID:
P49438
P48050
MRPS77346
facet_what:
Moon
facet_what:
Jupiter
facet_what:
Voyager
facet_what:
Earth
facet_what:
Galileo
facet_what:
Galileo Orbiter
facet_what:
Ganymede
facet_what:
Ganymede (Jupiter Moon)
facet_where:
Jet Propulsion Laboratory
facet_where:
Jupiter
facet_where:
Washington
facet_where:
Ganymede
facet_where:
Jet Propulsion Laboratory (JPL)
facet_where:
Washington, D.C.
Image #:
PIA00519
UID:
SPD-PHOTJ-PIA00519
orignial url:

Ganymede G1 & G2 Encounters - Interior of Ganymede