A recent study has dated the Moon's largest impact feature, the South Pole-Aitken (SPA) basin, to over 4.32 billion years ago, making it the oldest confirmed impact site on the Moon.

This research indicates that the SPA basin likely formed between 4.2 and 4.3 billion years ago during a period of intense bombardment in the inner Solar System.

Conducted by a team from The University of Manchester, the study analyzed a lunar meteorite known as Northwest Africa 2995.

This meteorite, found in Algeria in 2005, is classified as regolith breccia and is believed to have originated from the SPA basin, providing valuable insights into the early Solar System.

The researchers estimated the age of the meteorite's materials by analyzing uranium and lead content, dating them between 4.32 and 4.33 billion years old.

NWA 2995's age was determined using radiometric dating, indicating it formed around the same time as the SPA basin.

Due to Earth's geological processes, evidence of ancient impacts is scarce, making lunar studies essential for understanding both lunar and terrestrial histories.

Professor Katherine Joy emphasized the need for future sample return missions, such as the Chang’e-6 mission, to validate the proposed age of the SPA basin.

The impact that created the SPA basin is believed to have been catastrophic, potentially caused by an impactor around 200 km in diameter, significantly larger than the Chicxulub impactor.

Published in Nature Astronomy, the study suggests that the SPA basin formed approximately 120 million years earlier than previous estimates, indicating a more gradual timeline for impact events on the Moon.

These findings challenge the long-held view that the Moon's most intense period of bombardment occurred between 4.2 and 3.8 billion years ago.

Understanding the timing of the SPA basin's formation is crucial for piecing together the history of impact events in the inner Solar System.