Mars’s two distinct hemispheres are a striking phenomenon that has puzzled scientists for decades. Unlike Earth, which is divided into similar northern and southern hemispheres, Mars’s Southern Highlands and Northern Lowlands have distinct characteristics. The elevated terrain of the former creates natural barriers to airflow, resulting in varied wind patterns and localized weather phenomena.
Researchers have long debated the origin of this dichotomy, with some suggesting giant impactors from space and others proposing large-scale convective movements of the mantle caused by temperature and density differences. A new study published in Geophysical Research Letters has attempted to unravel the mystery through the analysis of Martian earthquakes, or marsquakes.
Using low-frequency marsquake data recorded during NASA’s InSight mission, Professors Weijia Sun and Tkalčić identified a pattern of seismic attenuation that suggests the southern mantle experiences higher temperatures and lower viscosity. This, combined with the thicker southern hemisphere crust slowing heat loss from the interior, supports the conclusion that mantle convection is the primary cause of Mars’s unusual dichotomy.
The study’s findings contradict previous hypotheses that giant impacts are responsible for the hemispheres’ differences. Instead, the researchers propose a two-pronged approach to understanding the significant differences between present-day Mars and Earth. They plan to explore why Mars has a thicker crust than Earth and investigate the presence of liquid water on the planet.
Understanding Mars’s internal structure and evolution can provide valuable insights into the formation and future of our own planet. By studying Martian marsquakes, researchers hope to gain a deeper understanding of the solar system and its complexities.
Source: https://phys.org/news/2025-01-mars-distinct-hemispheres-mantle-convection.html