NASA scientists just peeked into the ultimate depths of Mars for the first time, according to a presentation at the virtual Lunar and Planetary Science Conference this week reported in the journal Nature. The agency's InSight spacecraft — which was placed on the Red Planet's surface to peer into the inner-workings of the planet, detected a seismic energy wave ringing through the Martian interior.
And this seismic wave revealed the physical size of Mars' core.
NASA's InSight data from Mars' core will reveal how the planet evolved
This latest measurement puts the radius of Mars' ancient core between 1,124 and 1,155 miles (1,810 to 1,860 km) — approximately half the size of Earth's unthinkably hot core. The Martian core is smaller than earlier estimates, which means it's less dense than scientists thought. But the discovery implies the core contains lighter elements — including oxygen, with sulfur and iron composing most of the Red Planet's core.
NASA's InSight team announced the new measurements during the virtual Lunar and Planetary Science Conference this week — which happened in Houston, Texas.
Both Earth and Mars are rocky planets, which means their layers are comprised of three basic layers: The crust, mantle, and core. As scientists come to know the distribution, composition, and density of Mars' internal layers, we will learn more about how the Red Planet formed and evolved into its modern situation.
Specifically, data from InSight's state-of-the-art instruments will enable scientists to determine how Mars' dense and metal-laden core separated from the rocky mantle above as the planet cooled through its lifespan. The Red Planet's core is likely still molten from its hellish creation, roughly 4.5 billion years ago.
Planets (even in our solar system) are extremely far apart — which is why the only other rocky planetary cores NASA has measured are the Earth's and the moon's. Knowing the insides of Mars will enable scientists to compare and contrast how different planets in the solar system evolved. Much like Earth, Mars used to have a strong magnetic field created from sloshing liquid in its core.
NASA's InSight may soon die
However, this magnetic field lost most of its power through Mars' long lifespan, allowing the Red Planet's atmosphere to escape into space — and much of its water was integrated into sub-surface minerals — leaving the planet surface a frigid, barren, and substantially less friendly to life than our planet.
The findings about Mars' core were reported by the Seismologist Simon Stähler of the Swill Federal Institute of Technology in Zurich, who says his team aims to publish the work for publication in a peer-reviewed journal, according to the Nature report.
This latest work comes on the heels of earlier discoveries from InSight that identified layers in the Red Planet's dusty crust. "Now we start to have that deep structure down to the core," said Philippe Lognonné, a geophysicist involved in the report, during the pre-recorded talk. Lognonné works out of the Paris Institute of Earth Physics in France, and is lead of the seismometer team for the InSight mission.
However exciting and admittedly historic this discovery is, the reveal of Mars' core size might be one of the last to come from NASA's InSight — since dust has rapidly piled onto its solar panels, which are 6.5-ft (2-m) wide. This puts a limit on the spacecraft's ability to generate power, and as Mars continues to reach its farthest position from the sun in its orbit, we may soon hear from InSight no more, as it joins an alien graveyard of expired probes scattered across the surface.