New analysis of seismic data from NASA's retired InSight lander has uncovered a surprising geological story beneath Mars' surface – a mantle filled with massive fragments from ancient celestial collisions. Published in Science, the findings suggest remnants of 4.5-billion-year-old impacts remain preserved in kilometer-scale clusters, offering unprecedented insights into planetary formation.
Researchers detected these anomalies through 1,319 marsquakes recorded between 2018-2022. The seismic waves revealed dense material up to 4km wide suspended in Mars' mantle – likely debris from primordial impacts that melted continent-sized portions of the young planet's crust.
"Mars acts as a cosmic time capsule," said lead author Constantinos Charalambous of Imperial College London. "Unlike Earth's geologically active mantle that erases such features, Mars' sluggish evolution preserved these impact remnants like fossils in planetary stone."
The discovery provides new context for understanding early solar system bombardment and planetary differentiation. Scientists speculate similar impacts shaped Earth's development, though subsequent tectonic activity erased direct evidence.
This research leverages InSight's legacy as the first mission to successfully deploy a seismometer on another planet, demonstrating how planetary seismology can unlock secrets of celestial bodies' interior composition and evolutionary paths.
