Mars is hiding a partially molten, far hotter southern half beneath its surface

A team led by Alexander Berne, publishing in Nature, has found that Mars is hiding a deep thermal divide: its southern interior is 200 to 400°C hotter than the north and partially molten. Using tidal tomography — reading how the Sun's pull on Mars shifts through the seasons, from data gathered by three orbiters — the researchers mapped the planet's interior almost like a medical scan. The hotter south helps explain Mars's crustal dichotomy, its magnetic anomalies, and the faster seismic-wave dissipation seen by NASA's InSight lander.