Mysterious structures that were previously hidden on the Red Planet are revealed on the map of Mars.

On Mars, "structures" that were concealed by dirt beneath a vanished ocean have been found by scientists.

The discovery was made by researchers at the Netherlands' Delft University of Technology as they were mapping the planet's gravity. Around the planet's north polar cap, the scientists discovered 20 features that are noticeably denser than the surrounding area.

The Red Planet had rivers and oceans billions of years ago, but during a drastic climactic shift, the water dried up. The geologic record of Mars, such as this sediment layer, which has since revealed several buried "anomalies," is now the only proof of these bodies of water.

One of the structures, which differ in size and shape, has a dog-like shape. It has perplexed experts. However, they think that volcanic activity or past meteor strikes may have compacted the structures. The findings, which were presented this week at the Europlanetary Science Conference in Berlin, require further investigation.

Lead author Bart Root, an assistant professor at TU Delft, stated in a statement: "These dense structures may have been formed by ancient impacts or may have been volcanic in origin. We have discovered about 20 features of various sizes scattered over the region around the north polar cap, one of which has a dog-like morphology. On the surface, they appear to be completely absent. However, gravity data gives us a fascinating look into the northern region's earlier history.

The scientists created a picture of Mars' gravitational field—the area of space surrounding a planet where its gravitational influence is felt—by using minute variations in satellite orbits. They took this action in an attempt to find hints on the distribution of mass in the planet's subsurface. The scientists then integrated these findings with information on the dynamics of the planet's deep interior and mantle, as well as the thickness and pliability of Mars' crust.

NASA's InSIGHT lander, which finished studying the crust, mantle, and core of Mars in 2022, made these discoveries. The discovery of 20 hitherto unidentified subterranean structures strewn around the planet's north polar cap enabled the researchers to produce a global density map of Mars.

The buildings range in size and shape and are between 19 and 25 pounds per cubic foot denser than their surroundings. Furthermore, a thick, smooth layer of sediment that may have once been a seafloor covers them. Mars was not the arid planet it is today billions of years ago. Oceans and rivers formerly covered it, but during a drastic climate shift, the water dried up.

Scientists have previously discovered strange features beneath Mars' surface. Large honeycomb-shaped crevasses, which are buried several of meters below Mars' equator and are probably created when the earth cracks and contracts due to sharp temperature drops, were discovered by China's Zhurong in December 2023.

However, Root and his group are finding it more difficult to the nature of these most recent structures and their origins. They currently have two primary theories. The structures were either produced by volcanic activity or were compacted by ancient impact events, such as meteor strikes. Scientists' long-held belief that Mars is a geologically dormant planet is called into question by this later theory.

Although research has indicated that Mars' geological activity is lower than Earth's, an increasing amount of data indicates that Mars isn't entirely "dead." Root's research contributes to this evidence in a completely different way than simply identifying structures that might have been created by volcanic activity.

The team's investigation not only identified the enigmatic structures but also suggested that there may still be active geological processes in Mars' mantle that could be supplying the largest known volcano in the solar system, Olympus Mons. Scientists predict that Olympus Mons, which is situated in the Tharsis Montes region close to Mars' equator, hasn't erupted in 25 million years.

Root and his colleagues discovered a much lighter mass 700 miles below the surface of the extremely dense underground geology of the Tharsis region. He thinks this material is a massive 1,000-mile-wide jet of magma in the mantle of Mars. Furthermore, this plume may be bubbling to the surface right now.

"This means we need to rethink how we understand the support for the Olympus Mons volcano and its surroundings," Root stated. It suggests that there may yet be ongoing internal movements on Mars. it, influencing and potentially creating new surface volcanic structures."