Scientists Have Probed the Core of Mars

• Researchers have confirmed what lies at the core of Mars.
• Using seismic data from NASA’s InSight lander, the team was able to determine things like composition, state, and density of the core.
• The core is fully liquid, unlike our own, and made mostly of iron-alloy.

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We now know for sure what lies at the core of the Red Planet.

Researchers were recently able to finally confirm the makeup of Mars’s core using seismic waves that traveled through the planet. Thanks to NASA’s InSight lander, we can now be certain that Mars has a completely liquid core made predominantly of iron-alloy, with uncommonly high amounts of sulfur and oxygen.

“In 1906, scientists first discovered the Earth’s core by observing how seismic waves from earthquakes were affected by traveling through it,” said Vedran Lekic, geologist and one of the authors of the paper detailing these results, said in a press release. “More than a hundred years later, we’re applying our knowledge of seismic waves to Mars. With InSight, we’re finally discovering what’s at the center of Mars and what makes Mars so similar yet distinct from Earth.”

In order to ascertain this information, the team tracked the aftermath of two literally world-shaking events through Mars—one was a marsquake (the Martian equivalent of an earthquake) and the other was the shock from a large impact. The seismic waves from theses events travel at different speeds depending on what they hit along the way, so those traveling through the core will move at different rates than those that miss the core altogether.

When researchers compare the waves that passed through the core to those that only passed through the mantle, they are able to read the signatures carried by the waves and sleuth out the core’s makeup—reading off everything from what state the matter is in and how dense it is, to what substances comprise the innermost region.

The “uncommonly high amounts of sulfur and oxygen” seem to be the star of this particular core-centric show. Apparently, the core of Mars is almost one-fifth lighter elements like those (as opposed to heavy elements like iron), a much higher percentage than what makes up our own core.

It should be said here that researchers were pretty sure of these results already. The data from InSight largely confirms what models of Mars’s core have been saying for some time, rather than challenging any kind of long-held hypothesis.

But that’s not to say the results aren’t exciting. Confirming models means we were correct, and that we can now move forward with probing our Martian-core-related questions without having to go back to the drawing board.

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Many of those questions revolve around formation, as the difference between Mars’s core and our own points to substantial variation in how the two planets formed. Understanding those formation processes is critical to scientists who want to understand why Mars and Earth are so different, or how planetary systems like our Solar System form in the first place.

“This was a huge effort, involving state-of-the-art seismological techniques which have been honed on Earth, in conjunction with new results from mineral physicists and the insights from team members who simulate how planetary interiors change over time,” Jessica Irving, a researcher and first author on the study, said in a press release. “But the work paid off, and we now know much more about what’s happening inside the Martian core.”