We discovered for the first time what is in the core of Mars  

Thanks to the amazing InSight lander

NASA’s InSight lander has been monitoring the seismic tremors of Mars for four years, providing us with valuable information about the Red Planet’s interior. Now, for the first time, seismic waves have been detected that penetrated the core of Mars, revealing that in the center of the planet there is an iron alloy in liquid form, while what surprised the scientists is that sulfur and oxygen were detected in it.

In 1906 scientists discovered the Earth’s core by observing how seismic waves from earthquakes were affected as they traveled through it. More than a hundred years later, we are applying our knowledge of seismic waves to Mars. With InSight, we’re finally discovering what’s hidden in the center of Mars and what makes Mars so similar to, and at the same time so different from, Earth. – Vedran Lekic, University of Maryland geologist

InSight uses seismic waves as an “acoustic X-ray”, recording each time they change speed as they pass through one material or are reflected by others, to produce maps of the planet’s interior. Until 2021, however, the core of Mars remained a mystery. Then, he detected a massive earthquake on the other side of the planet, as well as a large asteroid collision. Because these events took place on the other side of the planet, InSight was able to analyze a different kind of waves. Those that traveled around the planet and those that traveled through it, giving us the first seismic waves that we know moved through the core.

So unlike Earth’s core, which appears to have a liquid outer core, a solid inner core, and an even denser core within the inner core, Mars’ core appears to be all liquid. In addition, it appears to have a particularly high concentration of lighter materials in its inner core, with 1/5 of its weight consisting mostly of sulfur, with smaller amounts of oxygen, carbon, and hydrogen.

This means that the core of Mars is significantly less dense than that of the Earth and this may be due to the lack of atmosphere, since it has a weaker magnetic field.

It’s like a puzzle in a way. For example there are all these little traces of hydrogen in the core of Mars. This means that there would have to be certain conditions that allowed hydrogen to exist there, and we need to understand what those conditions were so that we can understand how Mars evolved into the planet it is today. This was a huge effort, with highly advanced seismological techniques derived from Earth observations, combined with new results from physicists and team members’ insights that simulated how planetary interiors change over time. But the work paid off, and we now know a lot more about what’s going on in the core of Mars.

The research was published in the Proceedings of the National Academy of Science .