关于这张图
When viewed from a distance with the sun directly behind NASA Cassini, the larger, brighter craters really stand out on moons like Dione. Among these larger craters, some leave bright ray patterns across the moon. The rayed crater seen here on Dione (698 miles, or 1,123 kilometers across) is named Creusa. The rays are brighter material blasted out by the impact that formed the crater. Scientists can use the patterns of ejecta (like these rays), to help determine the order of geological events on a moon's surface by examining which features lie on top of other features. This view looks toward…
