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Mars scientists ponder: Impact crater or supervolcano?

A cryptic crater on Mars continues to baffle in a new set of images from ESA's Mars Express spacecraft.

Amanda Kooser
Freelance writer Amanda C. Kooser covers gadgets and tech news with a twist for CNET. When not wallowing in weird gear and iPad apps for cats, she can be found tinkering with her 1956 DeSoto.
Amanda Kooser
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The ESA's Mars Express got a new look at an old crater.

ESA/DLR/FU Berlin

Impact craters are a common sight on Mars, but not every dish-shaped disturbance in the landscape is necessarily caused by a meteorite. The European Space Agency's Mars Express spacecraft has gifted us with a fresh look at a mysterious crater called Ismenia Patera.

The big question for scientists is whether Ismenia Patera is an impact crater or the remnants of a supervolcano.

"Patera" comes from the Latin for a shallow or flat bowl, an apt description for the formation that measures about 47 miles (75 kilometers) across. ESA shared several different looks at the crater, including a sideways perspective that helps the features pop.

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This perspective view of Ismenia Patera comes from ESA's Mars Express mission.

ESA/DLR/FU Berlin

ESA points to Ismenia Patera's irregular shape, uplifted rim and apparent lack of ejected material that would typically show up around an impact crater as evidence supporting the supervolcano theory. But the space agency says these features could "also be present in impact craters that have simply evolved and interacted with their environment in particular ways over time."

The supervolcano idea has been around since 2013, but we don't have any definitive answers yet on this particular Mars formation.

Mars Express captured its views of the enigmatic crater earlier this year and ESA shared them on Thursday. 

While craters like Ismenia Patera remain question marks, scientists have pinpointed some definite volcanoes on Mars, including the mountainous Olympus Mons, the largest volcano in the solar system.

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