关于这张图
A bright spot can be seen on the left side of Rhea in this image. The spot is the crater Inktomi, named for a Lakota spider spirit. Inktomi is believed to be the youngest feature on Rhea (949 miles or 1527 kilometers across). The relative youth of the feature is evident by its brightness. Material that is newly excavated from below the moon's surface and tossed across the surface by a cratering event, appears bright. But as the newly exposed surface is subjected to the harsh space environment, it darkens. This is one technique scientists use to date features on surfaces. This view looks towa…
