Is the Martian atmosphere in imbalance?

Planetary structure: InSight looks deep below the surface of Mars

Using the measurement data from the seismometer on board the InSight space probe, which has been on Mars since November 2018, Sizhuang Deng and Alan Levander from Rice University in Houston, Texas, were able to prove that the interior of the Red Planet is divided into several zones of different densities structured.

For this purpose, the two scientists evaluated the data from the period from February to September 2019. They analyzed more than 170 earthquake events on Mars. To do this, they used sophisticated computer programs to filter out the subtle information about the interior of Mars from the highly noisy signals. The results are now being published in the "Geophysical Research Letters".

Accordingly, Mars below the InSight landing site in Elysium Planitia consists of a crust of silicate rocks, a silicate rock mantle and a core of metallic iron. The crust is 35 kilometers thick below the probe; it is followed by the mantle of the planet, which extends to a depth of 1,520 to 1,600 kilometers. Below is the iron core, which extends to the center of Mars. A transition zone is reached at a depth of 1110 to 1170 kilometers below the surface; Below this, the silicate mineral olivine changes under the prevailing pressure and temperature conditions into the denser mineral wadsleyite. As a result, the density of the rock mantle increases by leaps and bounds without changing the chemical composition. Such a conversion is called an isochemical reaction in technical terms. This mineral transformation also takes place inside the earth, however, due to the considerably higher pressure and temperature values ‚Äč‚Äčthere, already from a depth of about 650 kilometers. This is where the transition from the upper mantle to the lower mantle takes place.

With the data from InSight it can now be seen that the internal structure of Mars corresponds to the general model conceptions of the interior of the planets. But now, for the first time, much more precise information about the actual conditions in the Red Planet is possible.