Japetus

Caption NASA originale:"This image reveals a heavily cratered surface and shows the boundary between Iapetus' bright trailing hemisphere and Cassini Regio - a large, dark region that covers the leading hemisphere of the moon's surface. Some of the dark material appears to have collected inside the rim of a large impact structure about 250 Km across that lies just beyond the edge of the dark region (seen here near the right of the image). NASA's Voyager images (see PIA02268) this feature appeared as a dark 'moat' and had been hypothesized to be an impact structure. The recent images from Cassini confirm an impact origin for this feature.