Photograph Description

Saturn’s moon Tethys. Cassini spacecraft image of Tethys (white) and the rings (across top) of its parent planet Saturn. Two large craters are seen on the moon’s surface; Odysseus at top right and Melanthius at bottom centre. Tethys has a diameter of 1060 kilometres and is composed almost entirely of pure water ice. The high reflectivity (albedo) of the icy surface makes Tethys the brightest moon orbiting Saturn and one of the brightest objects in the solar system. Image obtained on 11th September 2005 by the Cassini spacecraft’s narrow-angle camera, at a distance of 2 million kilometres from Tethys. (Photo by Science Photo Library)