关于这张图
Surface features on Rhea -- mostly impact craters in this image -- are thrown into sharp relief thanks to long shadows. Viewing this terrain near the day/night terminator makes it easier to appreciate just how violent Rhea's geological history has been. The craters on Rhea (949 miles, or 1,527 kilometers across) are the result of 4.6 billion years of bombardment by small bodies. With very little erosion, the scars and craters remain unless they are overwritten by other, newer impacts. This view looks toward the anti-Saturn hemisphere of Rhea. North on Rhea is up and rotated 11 degrees to the…
