Mars hides a solid core similar to that of Earth

BarcelonaFor the first time, there is scientific evidence that Mars hides a solid inner core about 600 kilometers across, surrounded by a liquid core. Thus, the red planet is, in this respect, more similar to Earth than previously thought, although they have evolved very differently. The discovery was made from tests sent three years ago by NASA's InSight mission, in which Chinese and American researchers observed the behavior of Martian earthquakes between 2018 and 2022. Through comparisons with data from Earth, we can begin to decipher the evolution of Mars and how it lost its ancient magnetic field. It will also be used to analyze its thermal and chemical state.

According to a publication published this Wednesday by the journal NatureResearchers have identified phases of seismic waves—called PKiKP and PKKP—that can only occur if there is a boundary between a liquid and a solid core. The seismic waves in the PKKP phase reached the Insight lander's seismometer between 50 and 200 seconds earlier than would be expected if the core were purely liquid, suggesting the presence of a solid element in its structure.

Like Earth, Mars' solid core is made of iron, but unlike the blue planet, lighter elements—sulfur, carbon, and oxygen—are also present, making it much less dense. All of this is considered the result of a crystallization process.

With this new data, we can get a better idea of how Mars lost its magnetic field, which would allow life to thrive. The planet lost this field billions of years ago, and it is believed that the creation of the solid core could explain why. Unlike what happened on Earth, which has maintained it, the red planet no longer has it.

Evolution of rocky planets

But according to researchers, the study will not only help us better understand Mars, but they also hope it can solve mysteries about the evolution of other rocky planets in the solar system, including Earth.

The data collected by the Insight mission have been used in research by several groups outside of NASA, which, after a period of time, makes them available to other colleagues. As a result of this work, the same scientific journal recently published another study that refuted textbook illustrations of Mars with smooth, stratified layers—the crust, mantle, and core—and advocated depicting an interior that is an amalgamation. The planet's mantle contains ancient fragments up to four kilometers wide that date back to its violent formation and have been preserved as geological fossils.