Scientists Find Mars South 750°F Hotter Than North, Deepening Planet's Divide

3 articles · Updated · Space.com · Aug 31

Up to 750°F of extra heat appears to sit beneath Mars's southern hemisphere, with the mantle there potentially still partially molten, according to a Nature study published Aug. 27.
Researchers reached that result by reanalyzing gravity-driven orbital changes in data from Mars Global Surveyor, Mars Odyssey and Mars Reconnaissance Orbiter using a tidal tomography method that tracks solar effects on Mars.
The anomaly helps explain why InSight saw seismic waves fade faster in the south and why ancient magnetic signatures in southern rocks differ, pointing to a hotter interior long after Mars lost its global magnetic field.
That interior imbalance mirrors Mars's surface split—northern lowlands versus southern highlands with crust about 25 kilometers thicker—and could reshape ideas about the planet's volcanic history, hydrology and past habitability.
Scientists still do not know whether the divide came from a giant impact more than 4 billion years ago or from the south's thicker crust trapping heat, a question future gravity missions may test.