A satellite orbiting Mars has captured the best images ever of a giant “scar” carved across the Red Planet’s surface. The dark rift, which is surrounded by unusual zebra-like stripes, is likely the result of extreme volcanic activity millions of years ago.
The striking surface feature, called Aganippe Fossa, is a rift – a “trench-like groove with steep sides on both sides,” according to the European Space Agency (ESA). Astronomers spotted it in 1930, but didn’t officially name it until 1976, according to the US Geological Survey.
The graben is incomplete, with several breaks in the groove from end to end, but it is considered a single structure that extends about 375 miles (600 kilometers). That is longer than the Grand Canyon, which is 277 miles (446 km) from end to end, according to the National Park ServiceHowever, the structure is still significantly shorter than that of Mars. Valles Marineris — the largest canyon in the solar system, stretching more than 4,000 kilometers along the Red Planet’s equator.
ESA’s Mars Express orbiter took the newly released images on December 13, 2023. The satellite has been orbiting the Red Planet in an elliptical orbit for more than two decades.
One of the most interesting things about the image is the surrounding landscape, which varies on either side of the giant crack. On the left, the ground appears very uneven, with various hills, grooves and ridges. But on the right, the land appears smooth and painted with “zebra-like” rock stripes, ESA officials said.
This large difference was likely caused by historical wind erosion to the right of the rift, which has worn away the planet’s surface in that region. It is unclear, however, why the rest of the surrounding landscape was left untouched.
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Aganippe Fossa lies near the base of Arsia Mons, a 12-mile-high (20 km) extinct volcano on Mars’ Tharsis Plateau. This region contains two other large volcanoes, Pavonis Mons and Ascraeus Mons, and together the three extinct peaks form a near-perfect line perpendicular to the planet’s equator. The trio is flanked by Olympus Mons, the highest mountain peak in the solar systemwhich lies just outside Tharsis and rises more than 25 kilometers above the surface — about three times higher than Mount Everest.
The scar was likely caused by a large magma plume that formed long ago beneath Arsia Mons, pushing up the Earth’s crust and cracking the surface, ESA officials wrote.
It is currently unclear how old Aganippe Fossa is, but NASA previously estimated that the volcano stopped erupting about 50 million years ago. However, scientists have recently found evidence of a Volcanic eruption on Mars as recent as 50,000 years agosuggesting that volcanic activity on the Red Planet is not as old as previously thought.
Similar rifts also exist in Noctis Labyrinthus (meaning “Labyrinth of the night” in Latin) — a huge gulf the size of Italy, 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 caught the attention of researchers earlier this year after the discoveries of a giant volcano hidden next to Noctis Labyrinthus And more than 150,000 tons of frozen water over the peaks of the three Tharsis volcanoes.