“There appears to be no trace of them on the surface.”
Bury blast
New analysis of Mars' gravity field has revealed structures buried beneath the remains of an ancient ocean.
The work, which was presented this week at the Europlanetary Science Congress in Berlin, could add to growing evidence that suggests the Red Planet is not as geologically “dead” or inactive as previously believed.
Covered by a thick and smooth layer of sediment, these structures, which may have once been the sea floor, are much denser than their surroundings — though a more precise explanation of what they are has so far eluded researchers.
mark and away
These aren't the first oddities found in the interior of Mars. Last year, scientists revealed that China's Martian rover, Zhurong, found evidence of underground structures made of water ice deposits.
However, these latest anomalies are difficult to explain. According to lead author Bart Root, an assistant professor at TU Delft in Denmark, these structures — which are about 300 to 400 kilograms per cubic meter denser than their surroundings — may have been formed by some kind of volcanic activity, or they could have been compacted by ancient impact events, such as meteorite strikes, which have a long history on Mars.
“We identified about 20 shapes of various sizes in the area around the north polar cap — one of which resembles a dog,” Root said in a statement about the work.
“There appears to be no trace of them on the surface,” he said. “However, through the gravity data, we get a fascinating glimpse into the ancient history of the northern hemisphere of Mars.”
Thar Side
The discovery was made after images of Mars' gravity field were created using orbiting satellites, combined with geological data collected by NASA's InSight lander.
In addition to the dense structures, this also revealed another underground mystery: there appear to be still active processes in the Martian mantle, possibly powering Olympus Mons, the solar system's largest known volcano.
According to the work, the proof of this was the detection of another gravitational anomaly beneath a volcanic plateau called the Tharsis Rise — where Olympus Mons is located — indicating that this incredibly dense region is surrounded by a much lighter mass about 700 miles underground.
Root suggests it may be a giant plume of magma, about 1,000 miles in diameter, deep in the Martian mantle, slowly rising toward the surface.
“This means we need to rethink how we understand the support for the Olympus Mons volcano and its surrounding terrain,” Root said in the statement. “This suggests there may still be active movements inside Mars that could influence and possibly create new volcanic features on the surface.”
More information on Mars: Scientists discover huge reserves of water hidden on Mars