[7][8] The eastern lobe consists of high-albedo uplands thought to be coated by nitrogen transported through the atmosphere from Sputnik Planitia, and then deposited as ice.

[10] Photos, released on 15 July 2015, revealed 3,400 m (11,000 ft) mountains made of water ice in the feature; they also showed no craters in this same region.

[7] The surface of Sputnik Planitia is divided into polygonal convection cells[8] and is less than 10 million years old, indicating that Pluto is geologically active.

[12] The feature had been identified as a bright spot for six decades prior to the New Horizons flyby, although it was impossible to image it with enough resolution to determine its shape.

[18] Some people find that it also resembles the Disney character Pluto, an animated non-anthropomorphic dog which shares the name of the dwarf planet, in profile facing eastward.