Its strength was greater than that of the asteroid that ended the reign of the dinosaurs. A giant meteor shower hit the Moon, and certainly the Earth, 800 million years ago, according to a study published Tuesday in Nature Communications.
Thanks to data provided by the Japanese probe Kaguya, launched into orbit around the Moon in 2007, researchers at the University of Osaka (Japan) demonstrated that a gigantic asteroid at least 100 kilometers in diameter had erupted in several million billion meteorites that had plunged into the Earth-Moon system. This "bombardment" would have profoundly modified the environment and the biology of our planet.
Earth-Moon system hit by an asteroid shower 800 million years ago @ TeraKen0510 https://t.co/wyz4wygWEi pic.twitter.com/wtOFgDkhcR
- Nature Communications (@NatureComms) July 22, 2020Lunar craters studied
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 had formed simultaneously, following a gigantic asteroid rain.
Unheard-of strength
Given the probabilities of a collision, the study suggests that this episode certainly affected Earth as well. And with incredible strength since the global mass of these meteorites amounts to 40 to 50 million billion tons, or 30 to 60 times that of the asteroid that struck the current Yucatan peninsula in Mexico 66 million ago years and led to the disappearance of the dinosaurs.
This "bombardment" would have occurred just before the Cryogenian (between 720 and 635 million years ago), a period which experienced a 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.
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- Meteorite
- Asteroid
- Moon
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