Scientists May Have Finally Solved 50-Year-Old Mystery About Martian Surface

A groundbreaking study may have solved the 50-year-long mystery troubling scientists as to why one half of Mars is so drastically different from the other. The northern lowlands on the Martian surface are roughly 5-6 kilometres lower than the southern highlands, with the crust in the north being significantly thinner. Referred to as the 'Martain dichotomy', researchers have known about the divide since the 1970s when NASA's Viking orbiter returned images of the Red Planet's unusual surface.

The study published in the journal Geophysical Research Letters, suggests that the dichotomy might be due to internal heat transfer within Mars, rather than external cosmic collisions. Utilising data from NASA's InSight lander, researchers analysed marsquake data, which provided details into Mars' internal dynamics.

"At one point, Mars had moving tectonic plates like Earth does. The movement of these plates and the molten rock beneath them could have created something like the dichotomy, which was then frozen in place when the tectonic plates stopped moving to form what scientists call a "stagnant lid" on the planet's molten interior," the study highlighted.

The findings indicate that the dichotomy could be a result of mantle convection, where heat from the planet's interior shaped the crust over billions of years. The study's results were further supported by geochemical analysis of Martian meteorites, which provide clues about the planet's composition and thermal history.

Notably, the southern highlands are ancient, cratered and magnetised, dating back to the time when Mars had a global magnetic field. Meanwhile, the northern lowlands are younger, less cratered, and lack magnetisation.

Despite the findings, the study authors stated that more data on future marsquakes and comparative studies were necessary to fully confirm the theory.

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Mars' geomagnetic field

In November last year, a study by researchers at Harvard's Paleomagnetics Lab revealed that Mars' magnetic field, which could have supported life, may have lasted much longer than previously thought.

While Mars is now cold, barren and rocky, evidence suggests that the magnetic field may have lasted until 3.9 billion years ago, compared with previous estimates of 4.1 billion years -- making the Red Planet a prime candidate for a thriving environment for life.

The extra 200 million years overlap with the era when the Martian surface became covered with water, the evidence for which has been gathered by several rovers sent by NASA.