Unlocking Cosmic Secrets: How Fresh Marsquake Insights Illuminate One of Our Solar System’s Greatest Mysteries

Recent examination of marsquakes, which parallel earthquakes, may provide insights into the evolution of Mars over billions of years, as per novel research conducted by The Australian National University (ANU) and the Chinese Academy of Sciences. 

The results may shed light on the reason the southern hemisphere of the Red Planet, which encompasses roughly two-thirds of its surface, possesses a thicker crust and stands five to six kilometers higher in elevation than its northern hemisphere – a phenomenon termed the Martian dichotomy. 

The scholars suggest that the variances between the two regions of Mars were likely molded by convection – the movement of heat from one area to another – in the Martian mantle millennia to billions of years ago. The mantle is the middle layer of Mars located between the crust and the core. 

As per geophysicist and co-author of the study, ANU Professor Hrvoje Tkalčić, the disparity in the hemispheres of the Red Planet is “one of the greatest enigmas in the solar system”. 

“We examined waveform data from so-called low-frequency marsquakes detected by NASA’s InSight seismograph on Mars,” remarked Professor Tkalčić. 

“Through this process, we identified a group of six previously observed, yet unlocated marsquakes in the south highlands of the planet, specifically in the Terra Cimmeria area.” 

Co-author of the study, Professor Weijia Sun from the Chinese Academy of Sciences, contextualized the dichotomy. He mentioned that the elevation difference is “approximately equal to the height of the highest mountain ranges on Earth”. 

The investigators pointed out that the southern hemisphere is a less explored region of Mars. 

“The information derived from these marsquakes, in comparison with the well-recorded northern hemisphere marsquakes, indicates that the southern hemisphere of the planet is considerably hotter than its northern counterpart,” stated Professor Tkalčić. 

“Understanding if convection occurs provides insights into Mars’s development into its present state over billions of years.” 

Professor Tkalčić mentioned that there are two opposing theories to clarify the origins of the Martian dichotomy: the first, known as the endogenic hypothesis, posits that convection in the interior of the Red Planet gave rise to this dichotomy. 

The second perspective, referred to as the exogenic hypothesis, suggests that cosmic events in space influenced the hemispherical variations. 

The recent findings represent a significant advancement for the endogenic hypothesis. They provide the initial observational proof lending support to it. 

“On Earth, we possess thousands of seismic stations disseminated globally. However, on Mars, we only have one station, making it challenging to pinpoint the locations of these marsquakes with just a single instrument,” Professor Tkalčić explained. 

The researchers conveyed that the InSight lander could serve as a model for upcoming planetary missions. The InSight lander collected data on marsquakes, Martian climate, and the planet’s interior from 2018 to 2022. 

“Unraveling the genesis of this dichotomy could also bear some ramifications for the past climate changes on Mars,” said Professor Sun. 

The study features in Geophysical Research Letters.