A giant meteor shower hit the Moon 800 million years ago, according to a study released Tuesday. It certainly also touched the Earth, with a phenomenal force, superior to that of the famous asteroid which put an end to the reign of the dinosaurs.
Thanks to data provided by the Japanese Kaguya probe, launched into orbit around the Moon in 2007, researchers at Osaka University have shown that a gigantic asteroid at least 100 kilometers in diameter had burst into several million billion meteorites that had plunged into the Earth-Moon system.
This bombardment, which occurred 800 million years ago, would have profoundly modified the environment and the biology of our planet, suggests their study published in the journal Nature Communications. The probability of an asteroid of this size hitting our planet occurs approximately every 100 million years.
But on Earth, impact craters over 600 million years old are impossible to date, as they have been erased by erosion, volcanism, and other geological processes. Hence the idea of studying them on the Moon, where there is practically no erosion.
Scientists were able to date 59 large lunar craters – including that of Copernicus, which was to serve as the landing site of the Apollo 18 mission in 1971.
To achieve this, they notably analyzed the density of the small secondary craters formed all around by the ejection of pieces of rock, and discovered that at least 8 of the 59 large craters (including that of Copernicus) had formed simultaneously, at after a gigantic shower of asteroids. Given the probabilities of a collision, the study suggests that this episode certainly affected Earth as well.
With incredible force, since the global mass of these meteorites amounts to 40 to 50 million billion tons – or 30 to 60 times that of the asteroid which struck the current Yucatan peninsula in Mexico 66 million ago years and led to the downfall of three quarters of the species then living on Earth, including non-avian dinosaurs.
This bombardment would have occurred just before the Cryogenian (between 720 and 635 million years ago), a period which experienced general glaciation. “Our findings suggest that this surge of extraterrestrial elements may have influenced biochemical marine cycles, severe disruption of Earth’s climate, and the emergence of animals,” write the study’s authors.