A satellite orbiting Mars has captured the best images of a giant “king” carved into the Red Planet’s surface. The dark crater, which is accompanied by unusual zebra-like stripes, is likely the result of extreme volcanic activity millions of years ago.
The striking surface feature, called the Aganippe Fossa, is a graben—a “moat-like groove with steep walls on either side,” according to European Space Agency (ESA). According to US Geological Survey.
The graben is incomplete, with various faults in the groove from end to end, but is considered to be a single structure that extends about 375 miles (600 kilometers). That’s longer than the Grand Canyon, which is 277 miles (446 km) from end to end, according to National Park Service. However, the structure is still significantly shorter than that of Mars Dance Marineris — the largest canyon in the solar system, which runs more than 2,500 miles (4,000 km) along the Red Planet’s equator.
ESA’s Mars Express orbiter captured the newly released photos on December 13, 2023. The satellite has circled the Red Planet in an elliptical orbit for more than two decades.
One of the most interesting things in the photo is the surrounding landscape, which changes on either side of the giant fissure. To the left, the ground appears to be very uneven and contains several mounds, pits and ridges. But to the right, the ground looks smooth and is streaked with rocks “like a zebra,” ESA officials said.
This sharp change is likely caused by historical wind erosion to the right of the graben, which erodes the planet’s surface in that area. However, it is unclear why the rest of the surrounding landscape was untouched.
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Aganippe Fossa is located near the base of Arsia Mons, an extinct volcano 12 miles (20 km) on Mars’ Tharsis Plateau. This region contains two other large volcanoes, Pavonis Mons and Ascraeus Mons, and together the three dead peaks form an almost perfect line perpendicular to the planet’s equator. The trio is surrounded by Olympus Mons, e the highest peak in the solar systemwhich lies just outside Tharsis and stands over 16 miles (25 km) above the surface – about three times higher than Mount Everest.
The mark was likely caused by a large plume of magma that accumulated under Arsia Mons long ago, pushing the planet’s crust up and tearing the surface apart, ESA representatives wrote.
It is currently unclear how old Aganippe Fossa is, but NASA previously assessed that the volcano stopped erupting about 50 million years ago. However, scientists recently discovered evidence of one Volcanic eruption of Mars 50,000 years agohinting that volcanic activity on the Red Planet is not as ancient as we previously thought.
Similar grabens also exist in Noctis Labyrinthus (meaning “The labyrinth of the night“in Latin) – a massive canyon about the size of Italy, which is located between Tharsis and Valles Marineris.
The area around Tharsis is one of the most geologically interesting regions on the Red Planet. The region also attracted the attention of researchers earlier this year after the discoveries of a giant volcano hidden near Noctis Labyrinthus AND more than 150,000 tons of frozen water across the peaks of the three Tharsis volcanoes.