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 the rover’s mounted seismometer, Insight investigated, among other things, Exciting Earthquake Parade. And now, using these measurements, scientists are revealing for the first time details about the Red Planet’s deepest interior.
Marsbevingen
Its Insight seismometer to detect Martian earthquakes is the size of a volleyball and is placed on the surface by the probe itself. With these instruments, scientists can “hear” seismic events hundreds to thousands of kilometers away. And by measuring earthquakes like that, scientists can learn more about the exact material from Mars. Meanwhile, seismometers already have I picked up hundreds of Martian earthquakes. The scientists therefore provided more information about the depth and composition of the Martian crust and Martian mantle and core in three different papers.
Using seismic data, the researchers have now mapped the red planet’s crust, mantle and core. Photo: Chris Bickle/Science, with data from InSight Mars SEIS Data Service (2019)
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We know that the Earth is made up of several “shells”: a thin crust of light and hard rock that surrounds a thick layer of heavy, sticky rock, which in turn houses a core composed mainly of iron and nickel. Other Earth-like planets – including Mars – are believed to have similar structures. “Seismic data have now confirmed that Mars may have melted once completely before splitting into the crust, mantle, and core we see today,” said study researcher Amir Khan. “But this is different from the one on Earth.”
Shell
The researchers found that the Martian crust, beneath the InSight landing site at the equator, is between 20 and 37 kilometers thick. This is interesting. It is much thinner than expected. This means that such a thin crust likely contains a relatively high proportion of radioactive elements, casting doubt on earlier models of the crust’s chemical composition.
Cancer
Beneath the crust we find the mantle extending about 1,560 kilometers below the surface. Measurements show that this mantle is morphologically similar to Earth’s upper mantle. In this sense, Mars’ mantle is actually a simpler version of Earth’s mantle. But measurements also reveal differences in chemical composition. For example, Mars’ mantle contains more iron than Earth’s. However, theories about the complexity of the Martian mantle also depend on the size of the underlying core – and it is here, too, that researchers have come to new conclusions.
uneducated man
The radius of Mars’ core is about 1,840 km, making it more than 200 km larger than was thought 15 years ago when the InSight mission was planned. The researchers can now recalculate the size of the core using the measured seismic waves. “After determining the radius of the nucleus, we can now calculate its density,” said researcher Simon Stähler. “If the core radius is large, the core density should be relatively low. This means the core must contain mostly light elements other than iron and nickel.” These include sulfur, oxygen, carbon and hydrogen, and make up for an unexpectedly large proportion. Although the composition of the entire planet has not yet been fully determined, data confirms that its core is liquid.
big earthquake
These results are just the beginning. Scientists now have the hard data to refine their model of Mars and how it formed. In addition, Insight’s seismometers detect new earthquakes every day, although researchers are still waiting for a big one. To date, the largest recorded earthquake is around 4 degrees on Earth’s Richter scale, which cannot be described as very impressive. This type of weak earthquake also occurs regularly on Earth. “We wanted to see another big one,” said researcher Mark Banning. “Now we have to work very carefully to extract information from the data that has been collected. A big earthquake will make all of this a little easier.”
In any case, the results presented here confirm the immense success of the Insight mission. “This will end in about a year, when the lander’s solar cells can no longer generate sufficient power,” said researcher Domenico Giardini. “But we’re far from done 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.”
Specifically, scientists want to uncover how Mars’ internal dynamics cause the loss of its active magnetic field and all of its surface water. “This gives us an idea of whether and how this process can occur on our planet,” explains Giardini. “That’s why we’re on Mars: to study its anatomy.”
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