Overview
- The peer‑reviewed paper published in Nature on August 26, 2026 used tidal tomography on decades of gravity tracking from Mars Global Surveyor, Mars Odyssey and Mars Reconnaissance Orbiter to infer a 200–400°C temperature excess beneath Mars’s southern hemisphere.
- At the inferred temperatures the southern mantle would be partially molten, a state that could help explain southern crustal magnetic remnants and seismic attenuation observed by NASA’s InSight lander.
- Authors offer three testable origins for the anomaly: heat from a giant ancient impact, long‑lived mantle convection concentrated beneath the south, or heat trapped by thick southern crustal structure.
- Tidal tomography detects tiny changes in spacecraft velocities to map time‑varying gravity and reconstruct three‑dimensional interior structure, a method that can guide where future geophysical probes should go.
- Resolving the cause will require new, higher‑resolution gravity maps or a network of seismometers on Mars, and those measurements will shape future mission goals and our view of Mars’s habitability and geologic evolution.