Data show it’s liquid and rich in sulfur and oxygen.

Following a thorough examination of NASA's Mars lander data, scientists have successfully unraveled the enigma at the core of the Red Planet. In an announcement of their groundbreaking findings from the University of Maryland, the geologists behind this momentous discovery reveal that Mars' core consists of a viscous liquid iron alloy, notably enriched with sulfur and oxygen. 

The genesis of this hypothesis, as elucidated in a study published in the Proceedings of the National Academy of Sciences, stems from the analysis of seismic data obtained via NASA's InSight Mars lander. Over the course of several years, this mission diligently monitored the Red Planet's seismic activities until its conclusion in 2022. As one of the co-authors of the study pointed out, this methodology follows a historical precedent. 

"In 1906, scientists first discovered the Earth’s core by observing how seismic waves from earthquakes were affected by traveling through it.

More than a hundred years later, we’re applying our knowledge of seismic waves to Mars,” Vedran Lekic, an associate geology professor was quoted as saying.

The UMD geology team, including Lekic, arrived at their remarkable deduction by scrutinizing the wave patterns generated by two recorded events within the InSight data: a Marsquake (akin to an earthquake on Mars) and an impact event. The UMD statement says that by contrasting the travel times of these waves through Mars with those confined to the mantle, the team could estimate the material's density and compressibility that the waves traversed.

Ultimately, their analysis led them to conclude that Mars most likely harbors a completely liquid core, distinct from Earth's combination of a liquid outer core and solid inner core.

Furthermore, the UMD team was able to infer specific details about the core's chemical composition, notably highlighting the unexpectedly substantial presence of light elements - particularly sulfur and oxygen - in Mars' innermost layer.

While this discovery in itself is intriguing, it holds the potential to significantly advance research into planet formation. However, there is still an abundance of knowledge to be gleaned from this wealth of data.

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"Even though the InSight mission ended in December 2022... we're still analyzing the data that was collected," Lekic said, noting that InSight will continue to influence scientists’ understanding about the formation and evolution of Mars and other planets for years to come.

Unlike Mars, Earth’s core is made almost entirely of metal, specifically, iron (Fe) and nickel (Ni).

This research was supported by NASA with a substantial grant and the SSERVI Cooperative Agreement.