Collection:
NASA Planetary Photo Journal Collection Collection NASA Planetary Photo Journal Collection Collection
Title:
Europa and Callisto under the watchful gaze of Jupiter Title Europa and Callisto under the watchful gaze of Jupiter Title
Original Caption Released with Image:
One moment in an ancient, orbital dance is caught in this color picture taken by NASA's Cassini spacecraft on Dec. 7, 2000, just as two of Jupiter's four major moons, Europa and Callisto, were nearly perfectly aligned with each other and the center of the planet. The distances are deceiving. Europa, seen against Jupiter, is 600,000 kilometers (370,000 miles) above the planet's cloud tops. Callisto, at lower left, is nearly three times that distance from the cloud tops. Europa is a bit smaller than Earth's Moon and has one of the brightest surfaces in the solar system. Callisto is 50 percent bigger -- roughly the size of Saturn's largest satellite, Titan -- and three times darker than Europa. Its brightness had to be enhanced in this picture, relative Europa's and Jupiter's, in order for Callisto to be seen in this image. Europa and Callisto have had very different geologic histories but share some surprising similarities, such as surfaces rich in ice. Callisto has apparently not undergone major internal compositional stratification, but Europa's interior has differentiated into a rocky core and an outer layer of nearly pure ice. Callisto's ancient surface is completely covered by large impact craters: The brightest features seen on Callisto in this image were discovered by the Voyager spacecraft in 1979 to be bright craters, like those on our Moon. In contrast, Europa's young surface is covered by a wild tapestry of ridges, chaotic terrain and only a handful of large craters. Recent data from the magnetometer carried by the Galileo spacecraft, which has been in orbit around Jupiter since 1995, indicate the presence of conducting fluid, most likely salty water, inside both worlds. Scientists are eager to discover whether the surface of Saturn's Titan resembles that of Callisto or Europa, or whether it is entirely different when Cassini finally reaches its destination in 2004. Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini mission for NASA's Office of Space Science, Washington, D.C. Original_Caption_Rel eased_with_Image One moment in an ancient, orbital dance is caught in this color picture taken by NASA's Cassini spacecraft on Dec. 7, 2000, just as two of Jupiter's four major moons, Europa and Callisto, were nearly perfectly aligned with each other and the center of the planet. The distances are deceiving. Europa, seen against Jupiter, is 600,000 kilometers (370,000 miles) above the planet's cloud tops. Callisto, at lower left, is nearly three times that distance from the cloud tops. Europa is a bit smaller than Earth's Moon and has one of the brightest surfaces in the solar system. Callisto is 50 percent bigger -- roughly the size of Saturn's largest satellite, Titan -- and three times darker than Europa. Its brightness had to be enhanced in this picture, relative Europa's and Jupiter's, in order for Callisto to be seen in this image. Europa and Callisto have had very different geologic histories but share some surprising similarities, such as surfaces rich in ice. Callisto has apparently not undergone major internal compositional stratification, but Europa's interior has differentiated into a rocky core and an outer layer of nearly pure ice. Callisto's ancient surface is completely covered by large impact craters: The brightest features seen on Callisto in this image were discovered by the Voyager spacecraft in 1979 to be bright craters, like those on our Moon. In contrast, Europa's young surface is covered by a wild tapestry of ridges, chaotic terrain and only a handful of large craters. Recent data from the magnetometer carried by the Galileo spacecraft, which has been in orbit around Jupiter since 1995, indicate the presence of conducting fluid, most likely salty water, inside both worlds. Scientists are eager to discover whether the surface of Saturn's Titan resembles that of Callisto or Europa, or whether it is entirely different when Cassini finally reaches its destination in 2004. Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini mission for NASA's Office of Space Science, Washington, D.C. Original Caption Released with Image
Image Credit:
NASA/JPL/University of Arizona Image_Credit NASA/JPL/University of Arizona Image Credit
Produced By:
CICLOPS / University of Arizona Produced_By CICLOPS / University of Arizona Produced By
Mission:
Cassini Mission Cassini Mission
Spacecraft:
Cassini Orbiter Spacecraft Cassini Orbiter Spacecraft
Target Name:
Jupiter Target_Name Jupiter Target Name
Is a satellite of:
Sol (our sun) Is_a_satellite_of Sol (our sun) Is a satellite of
Instrument:
Imaging Science Subsystem Instrument Imaging Science Subsystem Instrument
Product Size:
846 samples x 1016 lines Product_Size 846 samples x 1016 lines Product Size
Primary Data Set:
Cassini Primary_Data_Set Cassini Primary Data Set
facet_what:
Sun facet_what Sun facet_what
facet_what:
Moon facet_what Moon facet_what
facet_what:
Jupiter facet_what Jupiter facet_what
facet_what:
Voyager facet_what Voyager facet_what
facet_what:
Earth facet_what Earth facet_what
facet_what:
Galileo facet_what Galileo facet_what
facet_what:
Saturn facet_what Saturn facet_what
facet_what:
Cassini facet_what Cassini facet_what
facet_what:
Europa facet_what Europa facet_what
facet_what:
Callisto facet_what Callisto facet_what
facet_what:
Titan facet_what Titan facet_what
facet_what:
Cassini Orbiter facet_what Cassini Orbiter facet_what
facet_what:
Magnetometer facet_what Magnetometer facet_what
facet_what:
Imaging Science Subsystem (ISS) facet_what Imaging Science Subsystem (ISS) facet_what
facet_where:
Jet Propulsion Laboratory facet_where Jet Propulsion Laboratory facet_where
facet_where:
Jupiter facet_where Jupiter facet_where
facet_where:
Arizona facet_where Arizona facet_where
facet_where:
Saturn facet_where Saturn facet_where
facet_where:
Europa facet_where Europa facet_where
facet_where:
Callisto facet_where Callisto facet_where
facet_where:
California facet_where California facet_where
facet_where:
Washington facet_where Washington facet_where
facet_where:
Jet Propulsion Laboratory (JPL) facet_where Jet Propulsion Laboratory (JPL) facet_where
facet_where:
Washington, D.C. facet_where Washington, D.C. facet_where
facet_when:
1979 facet_when 1979 facet_when
facet_when:
2004 facet_when 2004 facet_when
facet_when_year:
1979 facet_when_year 1979 facet_when_year
facet_when_year:
2004 facet_when_year 2004 facet_when_year
Image #:
PIA02861 Image_# PIA02861 Image #
UID:
SPD-PHOTJ-PIA02861 UID SPD-PHOTJ-PIA02861 UID
orignial url:
http://photojournal… orignial_url http://photojournal… orignial url

Europa and Callisto under the watchful gaze of Jupiter

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Europa and Callisto under the watchful gaze of Jupiter