Mars may have a much warmer southern mantle

Researchers combined decades of spacecraft-tracking data from Mars Global Surveyor, Mars Odyssey, and Mars Reconnaissance Orbiter to measure small time-varying gravitational effects. Their tidal-tomography model indicates that the southern mantle is roughly 200 to 400 degrees Celsius warmer than the northern mantle and may be partially molten.

The temperature is inferred from gravity rather than measured by a probe. The result may help explain southern magnetic anomalies, seismic attenuation, and processes that shaped basins capable of holding water, but the origin of the thermal asymmetry remains unsettled. The study adds habitability context; it does not report present-day volcanism, a habitable environment, or evidence of past or current life.

Why it matters

Planetary habitability depends partly on internal heat and geological evolution, making a three-dimensional view of Mars's interior relevant without turning geophysics into a life claim.

What the source establishes

Confirmed peer-reviewed Nature paper and Caltech summary. The thermal structure is model-derived, its cause is unresolved, and no life detection is involved.