Reacción a "The presence of a solid inner core has been detected on Mars"

I believe the article is of high scientific quality. It is based on seismic data from the InSight mission, which is a lander, a multi-probe that lands on the body being explored and does not have wheels.

InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) was a NASA mission that landed on Mars in 2018 and was active until the end of 2022. Its objective was to study the planet's interior, measuring seismic activity, internal heat, and the properties of the core and mantle. It is equipped with the SEIS seismometer, which detected hundreds of earthquakes or "marsquakes." Thanks to these seismic waves, it was possible to understand the internal structure of Mars, similar to how earthquakes are studied on Earth to understand the crust, mantle, and core.

The authors of the article present a very robust and apparently well-founded analysis. The discovery of a solid inner core on Mars is a result of enormous relevance for understanding the evolution of Mars and other rocky planets and moons. It is comparable in importance to the confirmation of the previously known liquid core. The authors present clear evidence with seismic phases and offer consistent estimates of the inner core's size and physical properties.

News compared to previously published data

Until now, it was known that Mars had a liquid core rich in light elements, but the existence of a solid core was not yet confirmed. In fact, previous work had concluded quite the opposite, that the core was completely liquid. This article provides the first direct and convincing identification of a solid inner core on Mars, which represents an important paradigm shift for understanding the thermal evolution of Mars. The fact that Mars continues to exhibit internal geological processes is very relevant for understanding whether it could still be a habitable planet.

The discovery has other implications:

1. It provides new clues to explain why Mars lost its global magnetic field.

2. It helps to understand the processes of iron crystallization and core formation on rocky planets and moons in general.

3. Implications of the discovery for the current habitability of Mars:

In principle, the fact that Mars has a solid inner core surrounded by a liquid outer core is directly related to the planet's magnetic evolution, and this is very important because it has implications for its past habitability.

For example, on Earth, the growth of the solid core releases heat and light elements into the liquid core, which maintains the dynamo that generates the magnetic field. This field protects the atmosphere and surface from solar and cosmic radiation, which is key for life.

The discovery of a solid core on Mars indicates that in the past it may have also sustained an active dynamo, consistent with the existence of a strong magnetic field 4 billion years ago. This magnetic field would have protected the atmosphere and allowed for more habitable conditions on the surface. However, the study suggests that crystallization is too slow today to sustain a global magnetic field. This would explain why Mars has lost its magnetic shield, facilitating the loss of its atmosphere, eroded by the solar wind, and drastically reducing its current potential habitability.

This discovery does not mean that Mars is now habitable, but it confirms that in the past it had an active core and a global magnetic field, which would have favored the existence of stable liquid water on the surface and more benign conditions for life.

[Regarding possible limitations] The study is solid, but has obvious limitations, as it is based on a very limited set of seismic records from the InSight mission. Furthermore, although it confirms the existence of a solid inner core, it still does not allow us to precisely detail its exact composition or its role in the current internal dynamics of the planet.