Scientists believe they have been able to accurately determine the age of the largest and oldest impact basin on the Moon (more than 4.32 billion years ago). The Moon, like Earth, has been bombarded by asteroids and comets since its formation, leaving behind craters and basins. But the exact timing and intensity of many of these events, particularly the oldest and largest basin on the Moon, has remained elusive for scientists until now.

By analyzing the lunar asteroid known as North West Africa 2995, a team of scientists from the University of Manchester investigated the age of the massive South Pole-Aitken Basin (SPA) on the far side, the oldest confirmed lunar impact site. The length of the Moon is over 2,000 kilometers.

The suggested date is approximately 120 million years before the period when impact bombardment of the Moon is thought to have been at its peak. Invention published today Nature AstronomyIt gives a clearer picture of the Moon’s early collision history.

University of Manchester Royal Society University Research Assistant Dr. Joshua Snape said: ‘Scientists around the world have studied lunar meteorites as well as rocks collected by the Apollo, Luna and Chang’e 5 missions for many years. and created a picture of when these shocking events occurred.

“For several decades, there was general agreement that the most intense period of impact bombardment was concentrated between 4.2 and 3.8 billion years ago, that is, between the first half-billion years of the Moon’s history.

“But now constraining the age of Aitken’s south polar basin to 120 million years ago weakens the argument for this narrow-period impact bombardment of the Moon and instead points to a more gradual process of impact over a longer period of time.”

The Northwest African 2995 meteorite was found in Algeria in 2005 and is what geologists call regolith breccia; This means that it contains pieces of different types of rocks that were once lunar soil, fused together due to the heat and pressure associated with an impact event.

By analyzing the amount of uranium and lead found in various minerals and rock fragments in the meteorite, researchers were able to detect materials dating back 4.32 to 4.33 billion years.

The team, which included the University of Manchester, the Institute of Geology and Geophysics of the Chinese Academy of Sciences in Beijing, the Swedish Museum of Natural History in Stockholm and the University of Portsmouth, then compared these results with data collected by NASA’s Lunar Prospector. . A mission that orbited the Moon between 1998 and 1999 and studied the composition of its surface.

The comparison revealed many chemical similarities between the meteorite and rocks in the SPA basin, confirming their relationship and allowing the identification of a new epoch.

Senior lecturer at the University of Manchester, Dr. Romain Tartese said: “The implications of our findings extend far beyond the Moon. We know that the Earth and the Moon were probably affected similarly in their early history, but the rock record on Earth uses what we know about the Moon to give us clues about conditions on Earth during the same time period.” We can use it.” .

This new understanding opens new avenues for future lunar exploration.

Professor Catherine Joy, of the University of Manchester, said: “The proposed ancient age of the South Pole-Aiken Basin of 4.32 billion years now needs to be tested with sample return missions collecting rocks from known locations within the crater itself.”