Scientists detect seismic waves on Mars for the first time

Although Insight’s mission ended in December 2022, researchers continue to analyze the data the lander collected.

For the first time, an international team of scientists observed a series of seismic waves traversing the core of Mars.

These observations revealed that the core of the red planet is smaller and denser than previously estimated (with a radius of approximately 1,780-1,810 km) and that it is composed of a completely liquid iron alloy with high percentages of sulfur and oxygen.

This discovery, made from measurements from NASA’s Insight lander, will provide a better understanding of how the planet originated and how it differs geologically from ours. In 1906 the Earth’s core was discovered for the first time, observing how the seismic waves caused by earthquakes were affected when passing through it.

The team was able to follow the progression of two seismic events (one caused by an earthquake and the other by an asteroid impact), which took place in the opposite hemisphere to that of the Insight.

By measuring the time it took them to pass through the core and comparing it to the mantle waves, and combining this information with other seismic and geophysical measurements, the researchers were able to estimate the density and compressibility of the material the waves traversed.

This shows that the core is probably completely liquid, unlike Earth’s core which has a liquid outer part and a solid inner core.

On the other hand, the Martian core contains a high proportion of light elements mixed within it. About one-fifth of its weight is made up of these elements (sulfur predominates, with smaller amounts of oxygen, carbon, and hydrogen).

This means that we are dealing with a much less dense core than Earth’s, and this difference points to different conditions in the formation of both planets.

And the final result of these processes of formation and evolution are those that may or may not give rise to favorable conditions for life.

“The uniqueness of the Earth’s core allows it to generate a magnetic field that protects us from solar winds, allowing us to conserve water,” says Schmerr.

In contrast, “the core of Mars does not generate this protective shield, which makes conditions on the planet’s surface hostile to life,” he adds.

Although this magnetic field is not present on Mars today, previous research indicates that it could have existed in the past, but it was losing certain elements and evolving in such a way that it went from being a planet with a potentially habitable environment to a hostile one.

Studying the interior of Mars – which has been the main goal of the Insight mission – will help researchers better understand how all rocky planets, including our own, formed.