The lunar surface is marred by impact craters, remnants of the collisions that have occurred over the past 4.5 billion years. The Orientale basin, the Moon’s most recently formed sizeable crater, stands out from the rest. The crater, which lies along the southwestern boundary between the near and far sides of the moon, appears as a dark spot ringed by concentric circles of ejecta that reach more than 900 kilometers (560 miles) from the impact location. Researchers now propose that whenever a large body slams into the Moon, seismic waves produced during the impact travel through the solid lunar material, inducing seismic shaking that causes landslides and surface settling.