Tectonics of Mars southern highlands, and the Tharsis plateau. Much tectonic study of Mars seeks to explain the processes that led to the planet's division into these three provinces, and how their differing characteristics arose. Hypotheses proposed to explain how the two primary tectonic events may have occurred are usually divided into endogenic (arising from the planet itself) and exogenic (foreign to the planet, e.g., meteorite impact) processes. This distinction occurs throughout the study of tectonics on Mars. In general, Mars lacks unambiguous evidence that terrestrial-style plate tectonics has shaped its surface. However, in some places magnetic anomalies in the Martian crust that
Moons of Mars remounted and put in a new dome, where it remains into the 21st century. The names, originally spelled "Phobus" and "Deimus", respectively, were suggested by Henry Madan (1838–1901), Science Master of Eton, from Book XV of the Iliad, where Ares summons Fear and Fright. In 1959, Walter Scott Houston perpetrated a celebrated April Fool's hoax in the April edition of the "Great Plains Observer", claiming that "Dr. Arthur Hayall of the University of the Sierras reports that the moons of Mars are actually artificial satellites". Both Dr. Hayall and the University of the Sierras were fictitious. The hoax gained worldwide