Rhea's Wisps in Colour Poster

Bright, wispy markings stretch across a region of darker terrain on Saturn's moon Rhea. In this extreme false-colour view, the roughly north-south fractures occur within strips of material (which appear greenish here) that are a different colour from the surrounding cratered landscape. The origin of the colour differences is not yet understood, but it may be caused by subtle differences in the surface composition or grain sizes making up the icy soil. Wispy markings were seen on the trailing hemispheres of both Rhea and Dione in images taken by NASA's Voyager spacecraft, and were hypothesized by some researchers to be the result of material extruded onto the surface by ice volcanism. Cassini's earlier revelation of the braided fractures on Dione led to speculation that Rhea's wisps might also be created by fractures.