Rubble-pile asteroids form when asteroids collide and their shards reassemble into new, shuffled asteroids. And when they do, according to a new study, they might give the renewed asteroid a temporary magnetic field.
This result might address a mystery that has baffled astronomers for years: Some metallic meteorites hold traces of magnetism as if they carry remnants of internal magnetic fields. That shouldn’t be possible. Even if a meteorite does contain iron, it isn't expected to have a circulating dynamo, like the one in Earth's inner core, which scientists think is necessary to generate a magnetic field.
