Illustration of the asteroid 16 Psyche.

The asteroid Psyche (artist’s impression) is one of the relatively small number of metal-rich asteroids identified so far. Models predict more such objects. Credit: Maxar/ASU/P. Rubin/NASA/JPL-Caltech

Planetary science

Asteroids in disguise: violent impacts might explain space-rock mystery

Metal-rich bodies could be hiding beneath the glassy remnants of celestial smash-ups.

Cosmic collisions might have shrouded many asteroids’ true identities by cloaking them in glassy rubble.

Theory suggests that the Solar System should include plenty of metallic asteroids. Such objects would have been created billions of years ago when embryonic planets slammed into one another and shattered, leaving their iron cores exposed. But asteroid surveys have found surprisingly few metal-rich asteroids.

Guy Libourel at Côte d’Azur University in Nice, France, and his colleagues designed experiments to mimic small impacts on the surface of an asteroid in space. The team shot tiny rock particles into pieces of steel and chunks of iron meteorite, creating high-energy collisions that covered the targets in a glassy surface.

This coating obscured the underlying metal, leading the researchers to suggest that the ‘missing’ iron-rich asteroids might just be hard to spot because they are cloaked in these glassy disguises. In 2022, NASA will launch a spacecraft to the iron-rich asteroid Psyche, where the craft will explore how impacts affect asteroids’ surfaces.