Mars' hemispheres are vastly different from one another. Scientists have explored beneath the planet's surface and uncovered the reason behind this divergence.

Mars, like Earth, has hemispheres, but their defining characteristics are markedly different—this phenomenon is known as Martian dichotomy. The southern highlands of the Red Planet are older, higher, and more cratered than the northern lowlands. The elevated terrain acts as a natural barrier for air flow, leading to varying wind patterns and contributing to localized weather events, as noted by PHYS.org.

Previously, scientists believed this was related to impacts from giant celestial bodies with diameters of about 2000 kilometers, as well as large-scale convective movements in the mantle caused by differences in temperature and density. In a new study published in the journal Geophysical Research Letters, researchers attempted to unravel this mystery once again.

In this new work, the researchers focused on studying Martian earthquakes, also known as marsquakes. It's worth noting that, similar to Earth, this seismic activity can be utilized to investigate the mechanisms operating beneath the surface of Mars.

According to co-author of the study, Professor Weizhuo San from the Institute of Geology and Geophysics of the Chinese Academy of Sciences, Earth and Mars are often considered sister planets that formed around the same time—approximately 4.5 billion years ago. Both are located within the habitable zone of our solar system; however, Earth is home to an incredible amount of life, while Mars appears quiet and devoid of life.

The team believes that the contrast between the two planets is actually due to differences in their internal structures and processes. The dichotomy is one of the most striking features of Mars' surface topography and internal structures, and thus scientists hope to find answers to why life does not thrive on the Red Planet by investigating these planetary characteristics.

According to Professor Hrvoje Tkalcic from the Australian National University, while the picture of Earth's deep interior is becoming clearer, scientists still do not understand the interiors of other terrestrial planets. In the new study, they focused on examining the inner part of Mars using waves from marsquakes recorded by the InSight seismometer.

It is no secret that our understanding of the Solar System largely depends on our knowledge of Earth, and vice versa—understanding our planetary neighbor, scientists believe, will enable us to better comprehend the past of our own planet. To explore this, Professors San and Tkalcic utilized low-frequency marsquake data recorded during NASA's InSight mission, which took place between 2018 and 2022, aimed at studying the crust, mantle, and core of Mars.

The research findings indicate that Mars actually demonstrates significantly less tectonic activity compared to Earth, and as a result, the magnitude of marsquakes is considerably lower than that of terrestrial seismic events. Furthermore, the location of the seismometer on the surface exposes it to daily winds, which, despite protective shielding, lead to a significant reduction in the signal-to-noise ratio. Consequently, the researchers concluded that the Martian dichotomy is largely driven by mantle convection.