Researchers have discovered a major temperature imbalance deep inside Mars, with the planet’s southern interior appearing significantly hotter than its northern half. Gravity measurements indicate that the interior beneath the southern hemisphere is roughly 200 to 400 degrees Celsius (about 400 to 750 degrees Fahrenheit) warmer than the north, and it may be partially molten.
Scientists Uncover Massive Thermal Asymmetry Deep Inside Mars
The findings were detailed in a paper published in the journal Nature, titled Tidal Tomography Reveals a Thermal Anomaly Beneath Mars's Crustal Dichotomy.
The research was funded by NASA.
Unveiling Three-Dimensional Intricacies via Gravity Data
To determine the interior structure, the scientific team utilized a technique called tidal tomography, which measures how gravitational signatures vary over time.
Scientists usually assume that the interiors of planetary bodies are generally spherically symmetric, but this is not necessarily true,
lead author and University of Arizona planetary scientist Alexander Berne said in a statement.
As we get more gravity data, we can determine the three-dimensional intricacies of a planet’s interior structure,
Berne added. These inferences in turn give us a blueprint for designing future missions and scientific exploration of these worlds. Understanding the interior structure of planetary bodies helps us unravel the processes that shaped their formation and evolution.
Extending a Deep North-South Divide
Mars has long been recognized for its surface contrast. The southern hemisphere is dominated by tall mountains and heavily cratered terrain, standing several miles higher, while the northern hemisphere consists largely of broad, low-lying, relatively smooth plains. The new observations reveal that this dichotomy extends far below the surface.
The thermal anomaly may also help explain other previously observed phenomena. Scientists have detected unusual magnetic signatures in iron-rich minerals in the south, and a hotter southern mantle could indicate that Mars once possessed a magnetic field strong enough to produce magnetic differences between the two hemispheres. Additionally, NASA’s InSight mission previously found that seismic waves dissipate more quickly in the south, a characteristic that could be explained by a hotter region.
The dichotomy that we see between north and south is important to understand because it gives information about processes that may have influenced the hydrology of Mars, including the formation of basins that may have held water,
said Amirhossein Bagheri, a postdoctoral scholar at Caltech, co-author, and former member of the InSight team.
Investigating Origins and Unanswered Questions
Researchers do not yet know the exact cause of the thermal anomaly, and several hypotheses remain under consideration. One possibility is that a giant impact released heat from the north. Another suggests that spontaneous or regional convection may once have occurred within the southern Martian mantle. A third hypothesis is that thick geological structures and insulation by the thick southern highlands crust trapped heat and prevented it from escaping efficiently over several billion years.
The discovery leaves fundamental questions open in planetary science. Washington University in St. Louis planetary scientist Paul Byrne noted that questions remain, pointing out that the planet’s largest volcanic province sits on the margins between the north and south rather than in the much hotter southern mantle.
Co-author and Brown University planetary scientist Nick Wagner noted that the origin remains an ongoing question, stating that the study adds another line of evidence to help determine what is happening underneath the planet.
Research Team and Collaborators
Alongside Berne and Bagheri, co-authors of the study include Nicholas Wagner and Harriet Lau of Brown University, Isamu Matsuyama and Angela Marusiak of the University of Arizona, Sander Goossens of NASA Goddard Space Flight Center, Karwai Cheng of the Institute of Astronomy and Astrophysics at Academia Sinica in Taiwan, Antonio Genova of the University of Rome in Italy, Marc Rovira-Navarro of the Delft University of Technology in the Netherlands, Chuan Qin of UCLA, Douglas Hemingway of the University of Texas at Austin, Shijie Zhong of the University of Colorado Boulder, and Francis Nimmo of UC Santa Cruz.
По теме
