An Impactor Origin for Lunar Magnetic Anomalies

Abstract

Bringing Magnetic Materials to the Moon The Apollo missions to the Moon revealed that portions of the lunar crust are strongly magnetized. Lunar rocks are poor at recording the magnetic field, thus these magnetic anomalies have been difficult to explain. Based on numerical simulations of large-scale impacts, Wieczorek et al. (p. 1212 ; see the Perspective by Collins ) show that the vast majority of lunar magnetic anomalies can be explained by highly magnetic materials that originated outside the Moon and were delivered by the asteroid that hit the Moon and formed the South Pole–Aitken basin, the largest impact basin in the solar system.