3D mapping of Ceres reveals remnants of large craters

New Scientist : Simulations of the history of Ceres suggest that the dwarf planet should have 10 to 15 impact craters larger than 400 km across. Yet early images from NASA’s Dawn spacecraft, which has been in orbit around Ceres since March 2015, did not reveal any such craters. Now, Simone Marchi of the Southwest Research Institute in Colorado and his colleagues have created a three-dimensional model of Ceres from high-resolution images taken by Dawn. The model reveals large depressions on the surface of Ceres that Marchi and his team believe are the remnants of the expected craters. They suggest that Ceres’s unusual internal structure could be the reason for the smoothing. It is thought that Ceres’s surface hides a layer of mud that allows the outer layer to shift and relax, which Marchi’s team says would eliminate the telltale signs of large craters.