The data left by NASA’s spacecraft could explain why Mars, a planet once suitable for life just like Earth, is gradually dying.
In two new studies analyzing the legacy of InSight – NASA’s lander, which ceased operations in December 2022 – a team of American scientists discovered a previously unknown layer of nearly molten silicate surrounding Mars’ core.
This new finding contributes to understanding the mystery of why the Solar System produced three potentially habitable planets, yet today only Earth is rich in life.
Graphic depicting the structure of Mars with NASA’s spacecraft measuring seismic activity above, which “died” in 2022 due to Martian dust storms covering its solar panels – (Photo: IPGP-CNES).
Mars, along with Earth and Venus, are three rocky planets of similar size, located in the Goldilocks Zone (the habitable zone) of the Solar System, where the distance from the sun allows for a favorable environment and suitable temperatures for liquid water.
Venus underwent an unfortunate planetary evolution, turning it into a scorching, suffocating greenhouse world that rotates very slowly.
The history of Mars is more complex: Through evidence collected by NASA over decades, scientists firmly believe this world was once a “blue planet” like Earth, with oceans, rivers, and lakes.
Nasa even believes that ancient river valleys on Mars were once so flooded that many landers were sent there to search for signs of life.
The mystery of why the Red Planet has become the arid, harsh world it is today remains significant.
In 2021, an analysis of seismic data from InSight revealed that Mars’ structure is quite similar to Earth’s, including a large low-density core containing liquid iron and lighter elements such as sulfur, carbon, oxygen, and hydrogen.
However, these results indicated that the core has a higher ratio of light elements than is feasible.
The new analysis shows that this inconsistency is due to a layer of nearly molten silicate about 150 kilometers thick, the upper part of which was previously misinterpreted as the surface of the core.
Professor Vedran Lekic from the University of Maryland, the lead researcher, describes this silicate layer as a blanket surrounding the core, insulating it from cooling while concentrating radioactive elements whose decay generates heat.
“When that happens, the core cannot generate the necessary convection currents to create a magnetic field. This explains why Mars currently lacks an active magnetic field around it,” Professor Lekic explained.
The atmosphere on Earth serves as a protective shield for us and all life forms on the planet against harsh cosmic rays. The lack of a magnetic field is the reason Mars has been damaged, losing all surface water and preventing life from continuing to thrive.
“The differences between Earth and Mars may stem from differences in internal structure and distinct planetary evolutionary paths“ – Professor Lekic concluded, highlighting how fortunate Earth has been on its evolutionary journey, granting us the opportunity to exist.
