Aerography of Mars
MARS is the second smallest planet in the solar system and is the fourth planet from the Sun. The surface area of Mars is roughly the size of all the landmass of Earth put together minus the oceans.
Named after the Roman God of war, Martius, and ruled by the Greek God, Aries, this dusty dry wilderness appears in rusty red hues. The red planet is called so due to the abundant presence of iron (III) oxide on its surface.
Since the study of physical features of Earth is called Geography, it is fitting to call the topographical study of Mars, Aerography.
The remarkable difference in the physical characteristics of the Northern and Southern hemispheres of the planet is known as the Martian Dichotomy. The Northern hemisphere is made up of smooth and non-volcanic lowland plains. Dark sands covering large areas in the lowlands are eroded, forming lonely inselbergs and debris flow alluvial fans. If Mars had oceans, this would be the place for it.
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On the other hand, the Southern hemisphere, which covers about two-thirds of Mars, constitutes about 1–2 km higher than its northern counterpart. Scientists suggest that this remarkable difference is attributed to a large celestial body that might have impacted the Southern Hemisphere of the planet about 4 to 15 million years after its birth.
In the western part of Mars lies the gargantuan volcanic plateau called the Tharsis Bulge. It is home to the Solar System’s most massive shield volcanoes. There are 12 large volcanoes spread over 4000 km and with an average elevation of 10 km. Four of the most remarkable volcanic features of this region are Arsia Mons, Pavonis Mons, Ascraeus Mons, and Olympus Mons.
Furthermore, the sheer heights of these Brobdingnagian volcanoes compared with Earth even leaves Mt. Everest a Lilliputian in size. Pavonis Mons, the shortest of the Tharsis Montes, stands at 14.1 km high while the height of Mt. Everest is 8.8 km. Lying to its north-west is the colossal Olympus Mons, with height three times that of Earth’s tallest mountain and spanning over an area of almost 600 km.
Tharis Montes’ sheer weight and immense volcanic activity resulted in the crust’s subsequent opening and forming a region called Valles Marineris. Known as the Grand Canyon of Mars, Valles Marineris extends over 4000 km east of the Tharsis Monts. This area is almost the size of the United States of America, whereas the Grand Canyon of Arizona is a mere 446 km long. Scientists agree that Valles Marineris was formed as a result of intense volcanic activity in the Tharsis Bulge, which created an enormous tectonic crack in the eastern hemisphere of the red planet, which was eventually broadened by erosion in the region. Upon further study, scientists believe that the bottom of some of this region contains layered minerals, leading up to the hypothesis of the presence of water in this region.
This region’s striking feature is an impact crater stretching up to 2300 km called the Hellas Impact Structure, which is also one of the largest impact craters in the Solar System. This region’s average depth is 4 km while reaching a depth of 8 km on its western edge, which marks the deepest point on the planet. There is evidence that the bottom of the crater is filled with volcanic material, and some suggest the presence of glacial ice. At the same time, other theories suggest that this crater must have served as the Great Lake of Mars at some point in time.
At the carter’s deepest spot, the atmospheric pressure rises from an average of 6.5 mbar at its surface to almost 12 mbar. This figure is just above the triple point of water, meaning water can exist in its three states. However, if this number were below the triple point of water, as is the case on the Martian surface, water would have only existed in two states; gaseous and solid. Therefore, theories suggest that it is feasible for life to exist at this place.
Furthermore, the region between Tharsis highlands and Valles Marineris is called the Noctis Labyrinthus, the Labyrinth of the Night. It comprises of intersecting valleys of various sizes and steep slopes formed due to stress in plate tectonics. These faults are closely-spaced and heavily engraved, creating a complex grabens system.
Just like Earth, Mars’ North and South poles are covered in ice. These are known as Planum Boreum (north) and Planum Australe (south). The rotational tilt of Mars, at 25 deg, gives it the distinct four seasons like those on Earth (tilted at 23.5 deg). Owing to the tilted rotational axis and distance from the Sun, the Martian planet becomes cold enough to freeze carbon-dioxide in its atmosphere to ice. By mid-autumn, water ice and dry ice clouds form over respective hemispheres and the precipitation results in seasonal ice caps. By mid-spring, carbon dioxide from dry ice sublimates as temperatures begin to elevate.
Further to this, the North and South poles act as reservoirs of frozen carbon dioxide on the planet. In the events of terraforming Mars, these places can serve as the potential generators of air. Planum Boreum extends approximately 1500 km and has an ice sheet of almost 1 km, whereas discoverers also suggest the presence of a 20 km long glacial lake 1.5 km beneath the polar ice caps of Polar Australe. On the other hand, abundant permafrost exists at all the latitudes of the planet.
Extensive research is still required to formulate how much subsurface ice there is on the planet. Elon Musk postulates that humans will embark on the journey to the red planet by 2026. To colonize the planet, four basic needs must be met: breathable oxygen, crops for agriculture, building shelter and harnessing energy.
Hence, that future is not far where the stories that were the subject of sci-fi movies will come to life, and we shall witness the incredible journey of humankind from one planet to another.
