Overview

• A paper published in Science on Aug. 28 reports compositionally distinct fragments up to about 4 kilometers across scattered through Mars’ mantle.
• Using NASA’s InSight archive, scientists analyzed eight high-frequency marsquakes whose waves slowed and became scrambled at depth, signaling small-scale heterogeneity.
• Two of the events were recent meteorite impacts that left ~150-meter-wide craters and generated waves that probed deep into the mantle.
• The team interprets the fragments as remnants of colossal early collisions that produced magma oceans, with a fractal size pattern of a few large shards and many smaller pieces.
• Mars’ lack of plate tectonics likely preserved these features for billions of years, offering a time capsule that informs models for other rocky planets such as Venus and Mercury.