Umbriel . Uranus II . ... It is about the same size as Ariel and has about the same density. The surface appears to be old with large craters and does not change much from one location to another. ... Orbital period (days) . ... Visual geometric albedo . ... This image is a polar stereographic projection of the southern hemisphere of Umbriel. ... Dark regions are represented as red and bright regions are represented as blue. The two white regions are bright ejecta from two fresh craters. ...