Scientists Intrigued by “Negative Mass Anomaly” Under Surface of Mars

Why It Matters

Understanding this internal mass redistribution reshapes models of Martian evolution and informs future exploration strategies, including landing site stability and resource utilization.

Key Takeaways

• Mars day shortens by milliseconds each year.
• Negative mass anomaly located beneath Tharsis region.
• Buoyant mantle plume may drive new volcanism.
• Mass redistribution could accelerate planetary rotation.
• Study urges dedicated Mars gravity mission.

Pulse Analysis

The subtle acceleration of Mars’ rotation has moved from a curiosity to a measurable phenomenon thanks to NASA’s InSight lander. By comparing seismic and rotational data collected over the past decade with legacy Viking observations, scientists have confirmed that the length of a Martian sol is shrinking by a few hundred microseconds each year. Although the change is minute, it signals an active redistribution of mass deep within the planet—a finding that challenges the long‑held view of Mars as a geologically dead world.

The research team at Delft University of Technology attributes the spin‑up to a ‘negative mass anomaly’—a region of unusually low‑density, hot mantle material rising beneath the Tharsis volcanic province. Their computer simulations show that this buoyant plume can push lighter material toward the equator while denser rock sinks toward the rotation axis, much like an ice skater pulling in their arms to spin faster. The upward movement also creates melt pockets that may breach the 310‑mile‑thick lithosphere, potentially feeding the ancient volcanoes that dominate the Tharsis plateau. If confirmed, the anomaly reshapes our understanding of Martian interior dynamics and has practical implications for future missions.

A more active mantle could affect surface stability, geothermal gradients, and the feasibility of in‑situ resource utilization. Recognizing this, the authors advocate for a dedicated gravity‑mapping spacecraft to precisely quantify mass distribution and monitor rotational changes. Such data would refine planetary evolution models not only for Mars but also for terrestrial planets in general, offering a clearer picture of how internal processes drive surface geology and climate over billions of years.