The moon with the split personality, Iapetus, presents a puzzling
appearance. One hemisphere of the moon is very dark, while the other is
very bright. Whether the moon is being coated by foreign material or
being resurfaced by material from within is not yet known.
Iapetus' diameter is about one third that of our own moon at 1,436
kilometers (892 miles). The latest image was taken in visible light with
the Cassini spacecraft narrow angle camera on July 3, 2004, from a
distance of 3 million kilometers (1.8 million miles) from Iapetus
(pronounced eye-APP-eh-tuss).
The brightness variations in this image are not due to shadowing, they
are real. The face of Iapetus visible was observed at a
Sun-Iapetus-spacecraft, or phase, angle of about 10 degrees. The image
scale is 18 kilometers (11 miles) per pixel. The image was magnified by
a factor of two to aid visibility.
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 Cassini-Huygens mission for NASA's Office of Space
Science, Washington, D.C. The Cassini orbiter and its two onboard cameras
were designed, developed and assembled at JPL. The imaging team is based
at the Space Science Institute, Boulder, Colo.
For more information, about the Cassini-Huygens mission visit,
http://saturn.jpl.nasa.gov and the Cassini imaging team home page,
http://ciclops.org.
