Erg (landform) and western Asia, and Central Australia. In South America, ergs are limited by the Andes Mountains, but they do contain extremely large dunes in coastal Peru and northwestern Argentina. They are also found in several parts of the northeast coast of Brazil. The only active erg in North America is in the Gran Desierto de Altar () that extends from the Sonoran Desert in the northwestern Mexican state of Sonora to the Yuma Desert of Arizona and the Algodones Dunes of southeastern California. An erg that has been fixed by vegetation forms the Nebraska Sandhills (). Sand seas and dune
Geography of Pluto Geography of Pluto The geography of Pluto entails the delineation and characterization of regions on Pluto. Plutonian geography is mainly focused on what is called physical geography on Earth; that is, the distribution of physical features across Pluto and their cartographic representations. On 14 July 2015, the "New Horizons" spacecraft became the first spacecraft to fly by Pluto. During its brief flyby, "New Horizons" made detailed geographical measurements and observations of Pluto and its moons. Pluto may be defined as having retrograde rotation and an axial tilt of 60 degrees, or prograde rotation and a tilt of 120 degrees. Following