Scientists have determined that Mars‘ inner core is solid, much like Earth‘s. This conclusion comes from analyzing seismic data collected by NASA‘s InSight lander before its decommissioning in 2022. The research, led by Daoyuan Sun of the University of Science and Technology of China, utilized readings from over 1,300 marsquakes.
The study, published in the journal Nature, indicates a solid inner core extending approximately 380 miles (613 kilometers) from the planet’s center. This core is likely composed of iron and nickel, similar to Earth‘s core, but may also include lighter elements such as oxygen.
Surrounding this solid inner core is a larger liquid outer core, ranging from 380 miles (613 kilometers) to 1,100 miles (1,800 kilometers) from the center. The researchers believe the inner core’s crystallization process may have begun in the past and could still be ongoing.
Sun‘s team primarily relied on data from 23 relatively weak marsquakes, their epicenters located hundreds of kilometers from the InSight lander. The analysis suggests the solid inner core constitutes about one-fifth of Mars‘ radius, a proportion comparable to Earth‘s. However, the researchers caution that this similarity might be coincidental.
Nicholas Schmerr of the University of Maryland, not involved in the study, acknowledged the findings’ significance but emphasized that questions regarding Mars‘ core remain unanswered. He highlighted the lack of new seismic data since InSight‘s termination, emphasizing the need for future missions with more extensive seismic monitoring networks.
Further research, including more detailed modeling, is required to fully understand the inner core’s formation and its implications for Mars‘ magnetic field history. Currently, Mars lacks a global magnetic field, a phenomenon potentially linked to the slow crystallization of its core, according to Schmerr. The researchers hope that future studies will illuminate the details of the inner core’s shape and composition, as well as the nature of the boundary between the inner and outer cores. Further investigation into the possibility of a “mushy zone” near the core-mantle boundary is also warranted.
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