关于这张图
Saturn's rings are so expansive that they often sneak into Cassini's pictures of other bodies. Here, they appear with the planet in a picture taken during a close flyby of Dione. The flyby of Dione (698 miles or 1123 kilometers across) during which this image was taken was the last close encounter with this moon during Cassini's mission. The main goal of the flyby was to use the spacecraft as a probe to measure Dione's gravity field. However, scientists also managed to take some very close images of the surface. All of the data will be helpful to understand the interior structure and geologic…