Unveiling the Gravitational Veil of Olympus Mons

Recent investigations into the gravity field of Mars have uncovered fascinating structures lurking beneath the surface of Olympus Mons, the largest volcano in the Solar System. This research, which integrates findings from various Mars missions, suggests that dynamic geological processes within the Martian mantle may be influencing the growth of this colossal volcano.

At the Europlanet Science Congress (EPSC) in Berlin, Bart Root from the Delft University of Technology unveiled these groundbreaking findings. Using advanced techniques to analyze the gravity data, Root and his team identified multiple dense features hidden beneath a thick layer of sediment in the northern polar plains. This sediment is believed to have accumulated on what was once a vast ocean floor, creating a veneer that conceals Mars’ ancient geological history.

Dr. Root remarked, “These dense structures could be volcanic in origin or compacted material from ancient impacts. We’ve identified around 20 features of various sizes surrounding the northern polar cap.” One of the features even bears a striking resemblance to a dog, indicating the diversity of shapes that these hidden structures can take.

To comprehend the gravity field of Mars, the research team analyzed subtle variations in satellite orbits. This data was combined with insights from NASA’s InSight mission, which provided critical information about the thickness and flexibility of the Martian crust. The result was a global density map, revealing that the northern polar features possess a density of 300-400 kg/m more than the surrounding terrain.

Beyond the northern plains, the study shed light on the lesser-understood subsurface structures of the Tharsis Rise, a prominent volcanic region that hosts Olympus Mons. This area presents a peculiar enigma, as it’s located at a higher elevation than the Martian average but is surrounded by regions of lower gravity. Root’s team indicates that this anomaly cannot be entirely explained by surface variations alone; a lighter mass, approximately 1750 km wide and located about 1100 km beneath the surface, is likely contributing to the uplift of the Tharsis region. This mass may represent a plume of molten rock percolating through Mars’ interior.

Dr. Root elaborated, “The NASA InSight mission has provided critical new data about Mars’ outer layer, forcing us to rethink how Olympus Mons and its surroundings are supported.” This revelation implies that Mars may be home to active geological processes, which could lead to the formation of new volcanic features in the future.

In an exciting development, Dr. Root is part of the team advocating for the Martian Quantum Gravity (MaQuIs) mission. This proposed mission aims to map Mars’ gravity field with unprecedented precision, using technologies developed in previous Earth and Moon missions, such as GRAIL and GRACE. MaQuIs is expected to delve deeper into the Martian subsurface, providing insights not only into the enigmatic features beneath Olympus Mons but also into the dynamic processes occurring within the planet’s mantle.

As Dr. Lisa Worner of DLR stated, “MaQuIs would allow us to explore the Martian subsurface in greater detail, helping us understand these mysterious hidden features and the planet’s ongoing mantle convection.” Additionally, it could illuminate seasonal atmospheric changes and reveal the presence of groundwater reservoirs—key elements in comprehending Mars’ potential for past or present life.

The interplay of gravitational data, geological modeling, and advanced satellite observations is unveiling a hidden world beneath the surface of Mars. Understanding the structures and activity beneath Olympus Mons not only enhances our knowledge of Martian geology but also poses intriguing questions about the planet’s evolutionary narrative and its capacity to host life.