The Solar System's Largest-Known Canyon Is Stunning


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The Valles Marineris canyon on Mars is 10 times as long as the Grand Canyon and three times as deep (Credit: ESA.Int)

Mars is famous for its orangish-red hue caused by the iron oxide in its soil. However, the Red Planet's surface, which has been drastically altered by volcanoes, impact craters, crustal movement, and atmospheric conditions such as dust storms, is also home to a wide range of fascinating topographical features. High among the list is Valles Marineris — the Solar System's longest and deepest-known canyon.

The gargantuan gorge, which comprises a network of interconnected troughs, extends over 3,000 miles (4,826 km) — the distance between California and New York. It measures 200 miles (322 km) at its widest and 4.3 miles (7 km) at its deepest. In comparison, the Earth's Grand Canyon spans a "mere" 277 miles long, 18 miles wide, and about a mile deep!

This stunning HiRISE image of an east-facing slope of Valles Marineris's Tithonium Chasma was released on December 26, 2020 (Credit: NASA/JPL/UArizona)

The canyon's existence was first revealed by NASA's Mariner 9 Spacecraft in 1972. Since then, the HiRISE (High-Resolution Imaging Science Experiment) camera aboard NASA's Mars Reconnaissance Orbiter — launched to study the Red Planet's geology and climate in 2005 — has captured several close-up images of Valles Marineris. However, despite the detailed breathtaking photos — like the one above, unveiled on December 26, 2020 — scientists are still unsure how the gigantic chasm formed on the Martian surface.

While the mighty Colorado River carved up the Grand Canyon, the Red Planet was too hot and arid to have a river powerful enough to slash such an enormous abyss across its surface. Therefore, European Space Agency (ESA) scientists believe that Valles Marineris may be the result of volcanic eruptions from the Tharsis region — a vast volcanic plateau in Mars' western hemisphere.

"As the Tharsis bulge swelled with magma during the planet's first billion years, the surrounding crust was stretched, ripping apart and eventually collapsing into the gigantic troughs of Valles Marineris," the agency wrote on its website.

The experts suspect that landslides and ancient rivers may also have played a role in sculpting the canyon into the planet's rusty red surface.

The Olympus Mons on Mars is the tallest-known volcano and mountain in the Solar System (Credit: Image by NASA, modifications by Seddon/ Public domain/Wikimedia Commons)

Valles Marineris is not the Red Planet's only interesting topographical feature. Mars is also home to the Solar System's largest volcano — Olympus Mons. Standing an impressive 13.6 miles (22 km )tall, it is about 2.5 times the height of Mt. Everest and has a diameter of 374 miles (624 km) — approximately the same size as the state of Arizona. Although most of the volcano formed over billions of years, some areas are just a few million years old, leading scientists to suspect Olympus Mons is active with the potential to erupt.

Curiosity's view of Phobos passing in front of Deimos – in real-time (Credit: NASA/JPL-Caltech/Malin Space Science Systems/Texas A&M Univ., Public domain, via Wikimedia Commons)

Also intriguing are the Red Planet's two small moons — Phobos and Deimos. Named after the horses that pulled Greek war god Ares's chariot, the satellites are believed to be captured asteroids. They are potato-shaped because they have too little mass for gravity to make them spherical. Scientists maintain that the innermost moon, Phobos, which is slowly moving toward the Red Planet, will most likely crash into the surface or break apart within the next 50 million years.



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