Direct Detection of Projectile Relics from the End of the Lunar Basin–Forming Epoch

The Rocks That Hit the Moon The cratered surface of the Moon bears witness to the numerous impacts it has suffered. Chemical signatures of these impacts have been detected indirectly. Now, Joy et al. (p. 1426 , published online 17 May; see the Perspective by Rubin ) report the detection and characterization of meteorite fragments preserved in ancient lunar regolith breccias from the Apollo 16 landing site. These meteoritic fragments represent direct samples of the population of small bodies traversing the inner solar system at around 3.4 billion years ago—the same time or just after the basin-forming epoch on the Moon.