2023-10-27 20:15:19
For four years, NASA’s InSight lander spacecraft recorded seismic movements on Mars using its seismometer. The data was transmitted to Earth for detailed analysis. Analyzing this data is not only useful for studying Martian earthquakes but also for finding out things about the core of Mars. The changes suffered by seismic waves as they pass through the center of the planet can reveal details about that region that would otherwise be impossible to find out.
Although InSight’s mission ended in December 2022, the data it collected is still and will be the subject of much analysis.
Working with InSight data, a team led by Amir Khan of the Swiss Federal Institute of Technology in Zurich (ETH) has made important discoveries about the internal structure of Mars.
Analysis of Martian earthquakes recorded by InSight, combined with computer simulations, offers a new image of the interior of the Red Planet. Between Mars’ liquid iron alloy core and its solid silicate mantle is a layer of liquid silicate (magma) about 150 kilometers thick. “The Earth doesn’t have a completely molten silicate layer like that,” Khan stresses.
This discovery also provides new and revealing information about the size and composition of the core of Mars, solving a mystery that the scientific community had not been able to explain until now.
An analysis of the first captured Martian earthquakes had shown that the average density of the core of Mars had to be significantly lower than that of pure liquid iron. The Earth’s core, for example, is made up of 90% iron by weight. Light elements such as sulfur, carbon, oxygen and hydrogen make up a combined total of about 10 percent by weight. Early estimates of the density of Mars’ core indicated that it was composed of a much higher proportion of light elements, around 20% by weight. “This represents a very large complement of light elements, bordering on the impossible,” says Dongyang Huang, of the Swiss Federal Institute of Technology in Zurich and a member of the research team.
The new observations show that the radius of Mars’ core is smaller than the initially determined range of between 1,800 and 1,850 kilometers. The new observations indicate that it is in the range of between 1,650 and 1,700 kilometers, which is about 50 percent of the radius of Mars. If the core of Mars is smaller than previously thought but has the same mass, it follows that its density is greater and, therefore, it contains less light elements. According to the new calculations, the proportion of light elements is between 9 and 14 percent by weight.
“This means that the average density of the core of Mars is still somewhat low, but is no longer inexplicable in the context of typical planet formation scenarios,” says Paolo Sossi of the Swiss Federal Institute of Technology in Zurich and a member of the team. research.
Analysis of Martian seismic data collected by the InSight lander’s seismometer, as well as computer simulations of the seismic properties of liquid metal alloys, have revealed that Mars’ liquid iron core is surrounded by a 150-kilometer layer of molten silicate. thick, as a consequence of which its core is smaller than previously assumed. The decrease in the radius of the core implies a greater density than previously estimated and this reconciles the interior of Mars with known science. (Image: © 2023 Thibaut Roger / NCCR PlanetS / ETH Zurich. CC BY-NC-SA 4.0)
The fact that the core of Mars contains a significant amount of light elements indicates that it must have formed very early, possibly when the Sun was still surrounded by nebula gas from which light elements could accumulate in the Martian core.
The study is titled “Evidence for a liquid silicate layer atop the Martian core.” And it has been published in the academic journal Nature, along with an independent study, carried out by Henri Samuel’s team, from the Paris Globe Physics Institute in France, which has reached a similar conclusion using complementary methods. (Source: NCYT from Amazings)
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