In an unprecedented achievement, NASA reveals the internal structure of Mars

Scientists have been able - for the first time - to determine the internal structure of Mars using seismic data collected by NASA's InSight probe.

These data made it possible to highlight the significant differences in the properties of the inner layers between the Red Planet and Earth.

According to a NASA press release, analysis of Insight data showed that Mars has a thicker mantle than expected, as well as a larger molten liquid core than we thought.

The results of these new discoveries - in which researchers from the Swiss Institute of Technology (ETH Zurich) and the University of Cologne, Germany - participated in 3 scientific papers that topped the latest issue of the scientific journal "Science".

The Insight probe contributes to finding out why the fate of Mars and Earth is different (NASA)

Mission "Insight"

After the formation of the solar system, Mars and Earth were very similar, each with a blanket of ocean covering the surface.

But over the next 4 billion years, Earth became temperate and ideal for life, while Mars lost its atmosphere and water and became arid as we know it today.

To find out why the fates of the two planets differ, scientists are seeking to discover more about the internal makeup of Mars.

The InSight probe, which landed on Mars in 2018, is one of the most important scientific missions that seek to achieve this goal by exploring the seismic activity of the planet.

The seismometer carried by the probe on the surface of the planet has recorded more than a thousand earthquakes, most of which are too small to be noticed by a person standing on the surface of Mars.

But a few were large enough to help the team get their first real glimpse of what's going on beneath the planet's surface.

Using data from two different types of seismic waves - shear waves and pressure waves - the researchers created a 3-D map of Mars.

Shear waves are characterized by the fact that they only pass through solid materials and are reflected back toward the interior of the planet when they reach the surface, while pressure waves penetrate solid materials, liquids and gases more quickly.

Measuring the differences in the transit times of the two waves of Mars' inner layers has allowed researchers to pinpoint the locations of earthquakes and give clues to its internal formation.

Thin crust and thick scarf

According to a press release issued by the Zurich Institute of Technology, researchers have discovered that the Martian crust under the probe's landing site near the Martian equator is between 15 and 47 kilometers thick.

The results showed that this thin crust contains a relatively high proportion of radioactive elements, which calls into question previous models of the chemical composition of the entire crust.

The Seismic Wave Meter of the InSight probe on Mars (NASA)

Beneath the crust lies the Martian mantle, a much more solid rocky mantle that is between 400 and 600 kilometers deep, twice the Earth's mantle.

This may be - according to the researchers - because there is only one continental plate on Mars, unlike Earth, which has 7 large and moving plates.

Measurements also showed that the Martian mantle is minerally similar to Earth's upper mantle, but seismology reveals differences in chemical composition.

The mantle of Mars, for example, has a higher iron content than the Earth's mantle.

Liquid pulp and larger than expected

Analysis of the seismic data recorded by Insight also established that the radius of the Martian core is about 1,840 km, making it 200 km larger than scientists previously assumed.

Mars has a larger liquid core than previously expected (NASA)

Due to Mars' small size compared to Earth, its massive core means that it is less dense than Earth's, and must contain a large proportion of the lighter elements in addition to iron and nickel.

These include sulfur, oxygen, carbon and hydrogen, which make up a larger proportion than scientists previously expected.

The researchers concluded that the composition of the Red Planet is not yet fully understood.

However, iron studies confirm that the core is liquid even though Mars no longer has a magnetic field.

InSight's mission is expected to end next year after its solar cells are no longer able to produce more energy due to dust accumulating on them, but in the meantime, more Mars' inner secrets could be revealed, the researchers say.