A Hidden Secret Found Inside Mars Is More Proof The Red Planet Isn't Dead
Published recently in the Nature journal, the study demonstrates that this massive heat difference renders the mantle beneath the southern hemisphere hot enough to remain at least partially molten. Scientists commonly assume that planets maintain uniform, spherically symmetric interiors. However, lead researcher Alexander Berne from University of Arizona proved that the Red Planet’s well-known superficial dichotomy also extends into its deep interior.
Since drilling is out of the question, the research team utilized a technique known as tidal tomography. By analyzing decades of archival tracking data from three NASA spacecraft (Mars Global Surveyor, Mars Odyssey, and Mars Reconnaissance Orbiter), the scientists measured tiny, subtle fluctuations in orbital velocity caused by Mars's gravitational field. As the planet moves through its eccentric, tilted orbit around the Sun, the star's gravity flexes the planet in seasonal patterns. Tidal tomography mapped these gravitational shifts over time to reconstruct an inferred model of the interior temperature structure.
This heat anomaly does tie together several lingering Martian enigmas. Astronomers have long puzzled over the so-called Martian dichotomy, whereby the southern hemisphere is covered in ancient, heavily cratered highlands with a thick crust, while the north features smooth, low-lying plains with a significantly thinner crust.
The trapped thermal energy in the south aligns with seismic observations from NASA's retired InSight lander, which recorded seismic waves dissipating far more rapidly through the southern interior. Additionally, the temperature explains localized magnetic remnants in southern iron-bearing minerals, suggesting a warm mantle once drove intense magnetic and volcanic activity.
Now, how Mars became thermally divided remains an open question. The leading theory posits that a cataclysmic impact hit the northern hemisphere over four billion years ago, stripping away the upper crust and allowing the northern mantle to cool rapidly. Alternatively, the unusually thick crust of the southern highlands may have acted as a planetary thermal blanket, trapping heat for billions of years.
