Mons Huygens Mons Huygens Mons Huygens is the Moon's tallest mountain (but not its highest point). It is about high and is located in the Montes Apenninus. The Montes Apenninus were formed by the impact that created Mare Imbrium. Adjacent is Mons Ampère to the west. Further west is the crater Huxley. The mountain was named after the Dutch astronomer, mathematician and physician Christiaan Huygens, it was officially named by the IAU in 1961. Mons Huygens is high, about the same height as Aeolis Mons located on Mars in the middle of Gale crater, and taller than Mons Hadley located on the
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