The story of the solar system is written upon the faces of its many
worlds, such as Saturn's icy moon Rhea, seen here in an image from
Cassini. The moon's many impact craters attest to its violent beginnings
and more than four billion years of subsequent history. Rhea is 1,528
kilometers (949 miles) across.
Most moons in the outer solar system are icy, in contrast to the rocky
inner planets and Earth's moon. When the planets and their moons first
formed around our Sun, conditions were cold enough at Saturn's distance
that ices could condense to form solid bodies like Rhea. Since its
formation, Rhea has been battered by the leftover debris of planet
building, although at a much lower rate for the past 3.8 billion years
or so.
North on Rhea is up and rotated about 20 degrees to the left. This view
shows principally the leading hemisphere on Rhea.
The image was taken in visible light with the Cassini spacecraft
narrow-angle camera on May 5, 2005, at a distance of approximately 1.4
million kilometers (900,000 miles) from Rhea and at a Sun-Rhea-spacecraft,
or phase, angle of 78 degrees. The image scale is 9 kilometers (6 miles)
per pixel.
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 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.
For additional images visit the Cassini imaging team homepage http://ciclops.org.
