Thanks to Marslander Insight, we now know more about the formation of the crust, mantle and core.
NASA’s Insight rover landed on Mars in 2018. Using a seismometer mounted on the rover, Insight researched, among other things, Exciting Earthquake March. And now, using these measurements, scientists are revealing for the first time details about the Red Planet’s deepest interior.
His Insight seismometer for detecting Martian earthquakes is about the size of a volleyball and was placed on the surface by the probe itself. With this instrument, scientists can “hear” seismic events hundreds to thousands of kilometers away. And by measuring such earthquakes, scientists can learn more about the exact materials that Mars is made of. Meanwhile, the seismometer already has I picked up hundreds of Martian earthquakes. Accordingly, scientists provide more information about the depth and composition of Mars’ crust and the mantle and core of Mars in three different papers.
We know that the Earth is made up of several “shells”: a thin crust of light and hard rock surrounding a thick covering of heavy, sticky rock, which in turn holds a core composed primarily of iron and nickel. Other Earth-like planets – including Mars – are believed to have a similar structure. “Seismic data has now confirmed that Mars may have melted once completely before splitting into the crust, mantle and core that we see today,” said study researcher Amir Khan. “But these are different from those on Earth.”
The researchers found that the crust of Mars, below the InSight landing site at the equator, is between 20 and 37 kilometers thick. This is interesting. This is much thinner than expected. This means that such a thin crust is likely to contain a relatively high proportion of radioactive elements, casting doubt on previous models of the crust’s chemical composition.
Under the crust we find the mantle extending about 1,560 kilometers below the surface. Measurements show that this mantle is morphologically similar to the Earth’s upper mantle. In this sense, the mantle of Mars is actually a simpler version of the Earth’s mantle. But the measurements also reveal differences in chemical composition. For example, the mantle of Mars contains more iron than Earth. However, theories about the complexity of the layers of Mars’ mantle also depend on the size of the underlying core – and here, too, the researchers came to new conclusions.
The radius of the Martian core is about 1,840 km, making it more than 200 km larger than was assumed 15 years ago when the InSight mission was planned. The researchers were now able to recalculate the size of the core using the measured seismic waves. “After determining the radius of the nucleus, we can now calculate its density,” researcher Simon Stähler said. “If the radius of the core is large, the density of the core should be relatively low. This means that the core should contain a large proportion of lighter elements in addition to iron and nickel.” These include sulfur, oxygen, carbon and hydrogen, and make up an unexpectedly large proportion. Although the composition of the entire planet has not yet been fully determined, the data confirm that the core is liquid.
These results are only the beginning. Scientists now have hard data to improve their models of Mars and how it formed. In addition, the Insight seismometer detects new earthquakes every day, although researchers are still waiting for a major earthquake. To date, the largest earthquake recorded around 4 degrees on the Earth’s Richter scale, which cannot be described as particularly impressive. These types of weak earthquakes also occur regularly on Earth. “We’d like to see another big one,” researcher Mark Banning said. “Now we have to work very carefully to extract information from the data that has been collected. A big earthquake will make all this a little easier.”
In any case, the results presented here confirm the great success of the Insight mission. “It will be over in about a year, when the lander’s solar cells will no longer be able to produce enough power,” said researcher Domenico Giardini. “But we are far from finished analyzing all the data – Mars still holds many mysteries for us, especially whether it formed at the same time and from the same material as planet Earth.”
In particular, scientists want to demystify how the internal dynamics of Mars caused the loss of its active magnetic field and all of its surface water. “This gives us an idea of whether and how these processes can occur on our planet,” Giardini explains. “That’s why we’re on Mars: to study its anatomy.”
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