Tharsis Montes Tharsis Montes The Tharsis Montes are three large shield volcanoes in the Tharsis region of the planet Mars. From north to south, the volcanoes are Ascraeus Mons, Pavonis Mons and Arsia Mons. Mons (plural "montes") is the Latin word for mountain; it is a descriptor term used in astrogeology for mountainous features in the Solar System. The three Tharsis Montes volcanoes are enormous by terrestrial standards, ranging in diameter from (Pavonis Mons) to (Arsia Mons). Ascraeus Mons is the tallest with a summit elevation of over , or base-to-peak. For comparison, the largest volcano on Earth, Mauna Loa in Hawaii,
Fictional planets of the Solar System Fictional planets of the Solar System The fictional portrayal of our Solar System has often included planets, moons, and other celestial objects which do not actually exist in reality. Some of these objects were, at one time, seriously considered as hypothetical planets which were either thought to have been observed, or were hypothesized in order to explain certain celestial phenomena. Often such objects continued to be used in literature long after the hypotheses upon which they were based had been abandoned. Other non-existent Solar System objects used in fiction have been proposed or hypothesized by persons with no scientific standing,