Anseris Mons Mons bedrock is actually pre-Noachian in age, perhaps dating back to over 4.1 billion years ago. The Anseris Mons massif has undergone a significant amount of erosion since it was uplifted. The flanks of the mountain have huge triangular re-entrants and associated spurs, which give the massif a broad, pyramidal shape. The re-entrants were likely produced through a variety of mass-wasting and periglacial/glacial processes. A large cirque-like re-entrant with channelized debris aprons or fans is present on the south side of the mountain. Anseris Mons Anseris Mons is an isolated massif (mountain) in the southern highlands of Mars, located at
Fictional planets of the Solar System fragments of a single planet was gradually abandoned over the course of the middle decades of the 20th century in favor of the conclusion that no planet had ever accreted in the region of the asteroid belt in the first place. In fiction, various other names were given to the same or similar concepts. Fictional planets in our Solar System beyond the orbit of Neptune have been employed many times as settings or references in science fiction. Following the general reception of Pluto as the ninth planet of the Solar System in 1930, a hypothetical additional planet was sometimes called