Thanks to seismic data collected by the InSight probe, an international team of researchers has made the startling discovery of a thin layer of molten silicate surrounding the Martian core. This discovery may provide new information about how Mars formed, evolved, and transformed into the barren planet it is today.
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[EN VIDÉO] InSight mission: Seis, a seismograph to study Mars NASA’s next mission is called InSight and aims to study the structure…
The internal structure of the Earth is known in particular thanks to numerous seismic measurements; While traveling in the bowels of our planet Seismic wavesSeismic waves It changes SpeedSpeed Depending on the environment they cross, and they deviate as they move from one environment to another. Thus, seismic waves are generally faster when the density of the medium increases, and they move more quickly in the medium solidsolid it is in LiquidsLiquids. In addition, some seismic waves only travel in solid media. Thus we know that our planet consists of A from the surface towards the center ShellShell Solid, they hang from the mantle with a rigid, but sticky behavior over large time scales. Below is the liquid outer core, surrounding the solid inner core.
Insight and the first seismometer on the Red Planet
If determining the internal structure of the Earth is relatively easy (the Earth, which is geologically active, regularly produces seismic waves that are measured by numerous seismometers on its surface), this is not the case for Mars: the planet is noticeably less active, but above all we They have no way to measure its seismic activity on site. Although many hypotheses trying to explain the internal structure of the Red Planet have emerged over the years, it was not until the arrival of the InSight probe, developed by the US space agency (NASANASA) in cooperation with the National Center for Space Studies (CNES) and the German Aeronautics CenterAstronautsAstronauts (DLRDLR).
Equipped among other things with a Seis seismometer (Seismic experiment of the internal structure(The InSight probe landed on the surface of the red planet on November 26, 2018. The results didn’t take long: according to recent work carried out using data from SeismometerSeismometer However, scientists were able to confirm for the first time that Mars’ core was entirely liquid, unlike Earth which has a solid seed at its centre. They also estimated the radius of this core to be about 1,830 kilometres, which is much larger than thought until then. At the same time, these data supported the idea that on the contrary Earth’s coreEarth’s coreThe core of Mars was not only made of iron, but it also contained lighter elements, such as sulfur. carboncarbon Or hydrogen.
SEIS (Seismic Interior Structure Experiment) is the main instrument of the US InSight mission. Developed by Cnes, it aims to measure Mars’ seismic activity. © Sines
New analysis reveals a more complex structure
But, in 2021, the impact of A meteormeteor On the surface of Mars, opposite the location of the InSight probe, it made it possible to clarify the internal structure of the red planet. The impact generated seismic waves that spread through his entrails. By analyzing it, an international team of researchers showed the existence of a new liquid layer between the liquid core and the cavity coatcoat Solid, unnoticed by anyone. They present their results in the journal nature.
According to their work, publishedenergyenergy Seismic surveys in the interior of Mars reveal a thin layer of molten silicate rock at the boundary between the core and mantle. According to this new model, this layer surrounds a liquid core that is smaller than previously thought, with a radius of about 1,650 kilometers.
This is also good news for scientists, who have not yet been able to explain the high content of light elements theoretically. The presence of a new liquid layer is also supported by observations of the planet deforming under the influence of gravitational interactions with its planet. moonmoon Phobos.
A second team of researchers, independent of the first, came to very similar conclusions, estimating the radius of Mars’ liquid core at about 1,675 kilometres. Their results are also published in the journal nature. According to them, the presence of a thin layer of molten rock between the core and the mantle could come from an ocean of molten rock. The son-in-lawThe son-in-law That once covered the planet. After cooling and solidifying in the rock, the magma has left behind a deep layer of radioactive elements that still release heat and keep the molten rock at the base of the mantle.
Although the InSight probe is no longer active today, future analyzes of the data it collected may lead to a more precise review of the internal structure of our nearby neighbor.