InSight: Mars Has a Larger, Less Dense and More Liquid Core


InSight: NASA’s InSight spacecraft revealed that Mars has an internal structure very different from the characteristics pointed out by the scientific community so far. Due to the inability to take samples, the space agency analyzed received data on “seaquakes” — earthquakes on the Red Planet — and showed that the planet has a thick crust and a thin underlying mantle layer — resulting in a larger, less dense and more liquid than expected.

Such features suggest that Mars may have formed millions of years before Earth, when the Sun was still undergoing a process of condensation from a cloud of glowing gas. This information was combined with mineral physics data found in the mantle, yielding the estimate that the size of the Martian core has a radius of around 1,830 kilometers, just over half its total radius.

In planetary evolution, starting with the accumulation of space dust, lighter materials are brought to the surface, while heavier components sink towards the center of the planet. New research has stated that the Martian core must contain high concentrations of sulfur and other light elements. That’s because, in experiments, compounds of liquid iron with sulfur do not solidify at the same pressures and temperatures found on Mars.

Thus, scientists believed that rocks like Mars had an iron-rich core, followed by a mantle and a crust—with a thickness now determined to be between 15 and 45 kilometers. The lithosphere is also believed to be between 400 and 600 kilometers in size, a layer thicker than any other of its kind on Earth.

This characteristic implies a higher concentration of radioactive heat-producing elements, which may help to explain why there is no magnetic field in the entire planet. This lack has other consequences for future manned exploration, as more resistant equipment to solar winds will be needed.

InSight’s role in unraveling the mysteries of Mars

The spacecraft landed in 2018 and contains a seismometer capable of detecting the most sensitive vibrations. Based on this device, it was possible to create a mapping of the interior of Mars — the first ever done on another planet.

There, there are no plate tectonics, which led the researchers to hypothesize that the vibrations observed since the beginning of the mission could be the result of meteorites that reached the surface or else from other internal processes in the lithosphere. However, they highlighted that it is difficult to confirm this theory, as the instrument is subject to climate variation — impacted by periods with many winds, capable of influencing the data.

Furthermore, chemical and thermal interactions of the Martian crust with the atmosphere can help define conditions for the possible existence of life on the Red Planet.


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