Scientists appear to have unravelled the mystery of Mars' "Martian dichotomy" - a contrast between its southern highlands and northern lowlands that's puzzled experts for over half a century.

Drawing on insights from NASA's InSight lander, researchers now believe that this dichotomy is caused by internal dynamics within the planet, rather than external space collisions.

The team's analysis of marsquakes unearthed signs that the red planet's distinct hemispheres were likely created by deep-seated thermal processes. This groundbreaking research has been documented in the Geophysical Research Letters journal.

The Martian dichotomy came to light in the 1970s following the Viking Probe's transmission of remarkably detailed Martian images back to Earth.

These images showed a dramatic elevation difference, with Mars' southern highlands towering nearly four miles above the smooth, flat northern lowlands.

The southern highlands are not only elevated but also have craters and remnants of magnetism from an era when Mars possessed a planetary magnetic field.

The northern lowlands have a younger, smoother face with no evidence of past magnetisation, and the crust beneath the southern terrain is significantly thicker.

The authors' hypothesis suggests the planet's surface was moulded by internal forces such as heat transfer and mantle dynamics. They wrote: "Through the analysis of InSight marsquakes, we have made significant progress in understanding this phenomenon.

"These findings, supported by geochemical analysis of Martian meteorites, provide valuable in situ seismological observations that support the 'endogenic' hypothesis, suggesting that mantle convection plays a crucial role in forming the Martian crustal dichotomy."

Researchers theorised that tectonic plate movements and molten rock dynamics in Mars' early history may have created an uneven crust. As the planet cooled, these movements stopped, forming a "stagnant lid" that preserved the different landscapes.

While this research sheds light on the origin of the Martian dichotomy, it doesn't completely solve it.

The researchers emphasise that additional marsquake data will be vital to validate their findings, as well as comparative studies involving Earth, Mars and other celestial bodies.