The liquid core of Mars is smaller and denser than previously thought. This has been determined by a research group using data from the NASA lander Insight, which was able to measure the seismic waves of two earthquakes in autumn 2021 that originated on the opposite side of the red planet. On their way to the probe, they had penetrated particularly deep into the interior of the planet and thus made this insight possible. The result also showed that previously collected data was not as precise. The conclusions reached at that time had to be corrected. It has now also been determined that about a fifth of the core of Mars is made up of sulfur, oxygen, carbon and hydrogen.
Luck and skill are key
As study leader Jessica Irving from the University of Bristol explains, the analysis required luck and skill. Luck was therefore provided by the two marsquakes that shook the subsurface of the red planet on August 25 and September 18, 2021. Both occurred far from Insight on the opposite side of Mars. One of the tremors was even caused by a meteorite impact, which allowed the source to be narrowed down particularly precisely. The fact that the comparatively weak signals were found in the measurement data at all is due to the experience that had already been gained up to that point. The combination has therefore resulted in the most detailed investigation of the interior of our neighboring planet to date.
Insight landed on Mars in November 2018 and spent more than four years using a sensitive seismometer to measure waves produced by subsurface earthquakes. The aim was such conclusions about the interior of the planet, as they have now been presented again. Aside from isolated meteorite impacts, the tremors in the crust of the “one-plate planet” are caused by stresses in the rock caused by the slow shrinking of the cooling planet. Plate tectonics processes like those on Earth do not exist on Mars. In the summer of 2021, it was still said that the core of Mars is larger than expected. The new study has now appeared in the Proceedings of the National Academies of Sciences.
The Mars probe itself stopped working just before Christmas Eve 2022. This was due to dust that had accumulated on the solar panels. This ensured that Insight had less and less power available. “Approximately” 300 Wh per Martian day are needed for the extensive functionality of the probe, since the beginning of October between 280 and 310 have always been available. For a long time, NASA had hoped that a storm would once again clear the dust from the solar collectors. When exactly the probe would stop working could not be predicted in advance. The probe said goodbye with one last picture.
(my)
