关于这张图
The Cassini spacecraft is closing in fast on its first target of observation in the Saturn system: the small, mysterious moon Phoebe, only 220 kilometers (137 miles) across. The three images shown here, the latest of which is twice as good as any image returned by the Voyager 2 spacecraft in 1981, were captured in the past week on approach to this outer moon of Saturn. Phoebe's surface is already showing a great deal of contrast, most likely indicative of topography, such as tall sunlit peaks and deep shadowy craters, as well as genuine variation in the reflectivity of its surface materials. …
