NASA mission detects first seismic waves traveling through the center of Mars.

When quakes rumbled on Mars and a meteorite smacked into the red planet during the past four years, NASA’s InSight lander collected soundwaves that helped reveal secrets of the Martian interior.

During these events, InSight detected for the first time seismic waves traveling through the Martian core. Now, scientists have used the lander’s data to determine that Mars has a liquid iron-alloy core that also includes lightweight elements such as sulfur and oxygen, as well as smaller amounts of hydrogen and carbon.

Developing a greater understanding of the Martian interior can help scientists learn more about how rocky planets such as Earth and Mars form, how the two planets differ, and the factors that help make other planets habitable for life.

A study detailing the findings was published Monday in the journal Proceedings of the National Academy of Sciences.

“In 1906, scientists first discovered the Earth’s core by observing how seismic waves from earthquakes were affected by traveling through it,” said study coauthor Vedran Lekic, associate professor of geology at the University of Maryland, College Park, in a statement. “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.”

Researchers analyzed how long it took seismic waves generated by one marsquake as well as a meteorite impact to travel through the Martian core, allowing them to estimate the core’s density and chemical composition.