Review of InSight data allows scientists to further refine their model of Mars’ interior
Using archive data from the now defunct InSight Mars lander, especially two seismic detections that came from the planet’s far side, scientists now believe that Mars’ central core is significantly different than Earth’s, being entirely liquid and made up of much lighter materials than expected.
To determine these differences, the team tracked the progression of two distant seismic events on Mars, one caused by a marsquake and the other by a large impact, and detected waves that traveled through the planet’s core. By comparing the time it took those waves to travel through Mars compared to waves that stayed in the mantle, and combining this information with other seismic and geophysical measurements, the team estimated the density and compressibility of the material the waves traveled through. The researchers’ results indicated that Mars most likely has a completely liquid core, unlike Earth’s combination of a liquid outer core and solid inner core.
Additionally, the team inferred details about the core’s chemical composition, such as the surprisingly large amount of light elements (elements with low atomic numbers)—namely sulfur and oxygen—present in Mars’ innermost layer. The team’s findings suggested that a fifth of the core’s weight is made up of those elements. This high percentage differs sharply from the comparatively lesser weight proportion of light elements in Earth’s core, indicating that Mars’ core is far less dense and more compressible than Earth’s core, a difference that points to different conditions of formation for the two planets.
These differences, if confirmed, would certainly affect the way Mars’ surface evolved over the eons, and might help explain its giant volcanoes as well as the planet’s lack of a magnetic field.
The results however remain uncertain, because InSight provided only one seismometer on Mars. To better triangulate the data will require more than one, in the future.
Using archive data from the now defunct InSight Mars lander, especially two seismic detections that came from the planet’s far side, scientists now believe that Mars’ central core is significantly different than Earth’s, being entirely liquid and made up of much lighter materials than expected.
To determine these differences, the team tracked the progression of two distant seismic events on Mars, one caused by a marsquake and the other by a large impact, and detected waves that traveled through the planet’s core. By comparing the time it took those waves to travel through Mars compared to waves that stayed in the mantle, and combining this information with other seismic and geophysical measurements, the team estimated the density and compressibility of the material the waves traveled through. The researchers’ results indicated that Mars most likely has a completely liquid core, unlike Earth’s combination of a liquid outer core and solid inner core.
Additionally, the team inferred details about the core’s chemical composition, such as the surprisingly large amount of light elements (elements with low atomic numbers)—namely sulfur and oxygen—present in Mars’ innermost layer. The team’s findings suggested that a fifth of the core’s weight is made up of those elements. This high percentage differs sharply from the comparatively lesser weight proportion of light elements in Earth’s core, indicating that Mars’ core is far less dense and more compressible than Earth’s core, a difference that points to different conditions of formation for the two planets.
These differences, if confirmed, would certainly affect the way Mars’ surface evolved over the eons, and might help explain its giant volcanoes as well as the planet’s lack of a magnetic field.
The results however remain uncertain, because InSight provided only one seismometer on Mars. To better triangulate the data will require more than one, in the future.
