Mars' Core Smaller and Denser Than Estimated, Surrounded by Molten Rock Layer: New Studies Reveal

New analyses of seismic data from NASA's InSight mission reveals previously unknown layer of molten rock straddling Martian core, indicates planet's thermal evolution and potentially sheds light on disappearance of Martian magnetic field.

Scientists have discovered a layer of molten rock, or silicates, surrounding the core of Mars, which is smaller and denser than previously estimated, according to two studies published in the journal Nature.
The discovery was made using seismic data from NASA's InSight mission to Mars. Although the mission officially ended in December 2022, analysis of the collected data is still ongoing.
The molten layer around Mars' core has been likened to a 'heating blanket', insulating the heat from the core and preventing it from cooling. It concentrates on radioactive elements whose decay generates heat, possibly explaining why Mars lacks an active magnetic field.
The presence of the molten layer indicates that Mars' core is smaller and denser than previously estimated, aligning better with other geophysical data and analysis of Martian meteorites.
Without a functional protective magnetic field, Mars is extremely vulnerable to harsh solar winds and loses all the water on its surface, which makes it incapable of sustaining life.
The existence of the molten layer supports theories that Mars was at one time a molten ocean of magma, which later crystallized to produce a layer of silicate melt, enriched in iron and radioactive elements at the base of Martian mantle. This dramatically altered the red planet's thermal evolution and cooling history.