Figure 1
This color composite image of Saturn's moon Iapetus from Cassini's visual
and infrared mapping spectrometer was obtained on Dec. 31, 2004, an hour
and a half before the New Year, at a distance of 121,000 kilometers
(75,186 miles), with a spatial resolution of about 60 kilometers (37
miles).
The three colors used in the mosaic correspond to 1.01, 3.21, and 3.80
microns. The different colors represent vastly different surface
compositions. The upper bright blue region is rich in water ice, while
the lower, dark brown region is composed mainly of a substance rich in
organic material. The yellow region consists of a mixture of ice and
organics, suggesting a gradual change in composition on the surface. This
pattern suggests Iapetus swept up the dark material, which may have come
from debris created from meteoritic impacts onto the small, outer
satellites of Saturn.
The Cassini-Huygens mission 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 mission for NASA's Science Mission Directorate,
Washington, D.C. The Cassini orbiter and its two onboard cameras were
designed, developed and assembled at JPL. The visible and infrared
mapping spectrometer team is based at the University of Arizona, Tucson.
For more information about the Cassini-Huygens mission visit, http://saturn.jpl.nasa.gov.
For more information about the visual and infrared mapping spectrometer visit
http://wwwvims.lpl.arizona.edu/.