February 16, 2007
Side-by-side natural color and false-color views highlight the wispy terrain on Rhea's trailing hemisphere.
The extreme false color image makes it clear that the wisps -- likely networks of fractures as on Dione -- cut across older, cratered terrain. In addition, a set of thin, north-south trending lineaments (also likely fractures) is visible on the left side of both views.
The natural color view was created by compositing images taken using red, green and blue spectral filters.
To create the false-color view, ultraviolet, green and infrared images were combined into a single picture that isolates and maps regional color differences. This "color map" was then superimposed over a clear-filter image that preserves the relative brightness across the body.
The combination of color map and brightness image shows how colors vary across the surface of Rhea. The origin of the color differences is not yet understood, but may be caused by subtle differences in the surface composition or the sizes of grains making up the icy surface material.
North on Rhea (1,528 kilometers, or 949 miles across) is up.
The images were taken with the Cassini spacecraft narrow-angle camera on Jan. 17, 2007 at a distance of approximately 597,000 kilometers (371,000 miles) from Rhea. Image scale is 4 kilometers (2 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 operations center is based at the Space Science Institute in Boulder, Colo.
Credit: NASA/JPL/Space Science Institute