Science
Martian mantle temperature differences may mirror its surface dichotomy
A new study using orbital radio tracking data suggests that Mars's interior is asymmetric, with a warmer southern mantle.
The short version
- A study published in Nature suggests that Mars's crustal dichotomy—where the rugged southern hemisphere stands higher than the smooth northern plains—extends deep into its mantle.
- Researchers analyzing orbital data estimated that the southern mantle is 200 to 400 degrees Celsius hotter and softer than the northern mantle.
- The finding could help clarify how Mars's interior asymmetry influenced its ancient habitability and the loss of its water.
Key facts
- A new study led by Alexander Berne used a technique called tidal tomography to reprocess 16 years of radio tracking data from three Mars orbiters.[Scientific American]
- The research team analyzed tiny variations in Mars's gravity field caused by tidal forces, finding that the mantle's stiffness varies by more than 20 percent between hemispheres.[Scientific American]
- Numerical simulations showed that the division between the harder northern rocks and softer southern rocks aligns closely with the boundary of the surface dichotomy.[Scientific American]
- A warmer southern interior aligns with a separate 2024 study that analyzed marsquake data from NASA's InSight lander, which suggested that seismic energy dissipates faster in the south.[Scientific American]
What remains uncertain
- External expert Amir Khan noted that the team's thermal interpretation relies on several modeling assumptions, meaning other explanations for the gravity data remain possible.[Scientific American]
- External expert Paul Byrne pointed out that Mars's largest volcanic province, Tharsis, is located on the boundary of the dichotomy rather than deep within the southern uplands where the mantle is reportedly hottest.[Scientific American]
Sources
- Mars may be two-faced to its coreScientific American metered