The ESA Says It Just Discovered an Ancient 'Supervolcano' on Mars
Mars is home to the largest volcano in the solar system, Olympus Mons, but the Red Planet may be tallying another supervolcano soon—according to photos from the ESA's Mars Express orbiter, a large depression on Mars' surface, which initially looked like a large impact crater, may in fact be the rim of a collapsed volcano.
In any case, the feature has been dubbed "Ismenia Patera" and stretches 75 kilometers wide.
Ismenia Patera sits on the border between Mars' northern lowlands and southern highlands, in an area called Arabia Terra.
The photos reveal a bumpy, hilly interior and what appear to be channels running from its rim to the area around it, suggesting magma flows. Though there are scattered rocks around the feature, there aren't quite enough to look like an impact crater.
The current hypothesis is that Ismenia Patera was an ancient supervolcano that erupted and subsequently collapsed, forming a caldera-like formation.
It's important to remember that Mars' volcanic activity is unlike anything Earth has ever seen—the Tharsis plateu, for example, is a group of volcanoes so vast that its emergence warped a large part of the planet.
The plateau is about 30,000 feet tall and 2,500 miles long, and may be the key to understanding the nature of Mars' oceans.
For size comparison, Mount Everest, the tallest mountain on Earth, is about 29,000 feet, while the Himalayas are about 1,500 miles long.
Ismenia Patera's supervolcano status isn't too difficult to imagine when Mars has already birthed giant volcanoes in the past.
On the other hand, Mars has roughly 635,000 large impact craters already, making it possible that Ismenia Patera is just a particularly large one that eroded and changed with the landscape until it started to resemble a volcano.