How Metal Meteorites Magnetize

A bout 8% of the Solar System’s asteroids are made mostly of metal. Like rocky and icy asteroids, metal ones occasionally suffer destructive collisions that send fragments—meteorites—hurtling toward Earth. Some of those meteorites have magnetic fields, a property whose origin planetary scientists have struggled to understand. Now Zhongtian Zhang and David Bercovici of Yale University have proposed a plausible explanation for the field’s presence [1]. If their scenario finds observational support, it could provide insight into howmodestly sized objects in other solar systems acquire magnetic fields.