Chinese scientists confirmed that the moon's oldest and largest impact crater, the South Pole-Aitken basin, formed 4.25 billion years ago. The finding, based on lunar samples from China's Chang'e-6 mission, offers new insights into the moon's early evolution. It suggests the basin was created by an asteroid impact in the solar system's first few hundred million years. The Chang'e-6 mission provided the first direct dating of the basin.