NASA’s InSight mission has detected giant fragments of rock from massive impacts 4.5bn years ago deep within Mars’ mantle, Xinhua reported.

Up to four kilometers across, these lumps reveal that Mars’ interior has evolved slowly, preserving ancient features that would have been erased on Earth. The impacts melted large areas of crust and mantle, embedding debris deep in the planet.

According to Xinhua, InSight recorded over 1,300 marsquakes, providing the detailed data behind this discovery.