José Manuel NievesSEGUIR Updated: Save Send news by mail electrónicoTu name *
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A team of researchers from the japanese university of Osaka in-depth study of 59 lunar craters of more than 20 km in diameter and has come to a surprising conclusion: all of them were formed after a large asteroid of more than 100 km diameter to disintegrate a few 800 million years , “watering” with its fragments of both the Moon and the Earth. The results of this work have just been published in Nature Communications.
The scientists ‘ analysis, based on data from the cameras of the probe lunar Kaguya , the space agency japanese JAXA , indicates that at least 4 or 5 by 10 raised to the 16 fragments the asteroid ended up falling on our planet and its natural satellite. A huge number of rocks whose combined effects were between 30-and 60-times that of the Chicxulub impact , that 65 million years ago, during the Cretaceous period, caused on the Earth the mass extinction of nearly 70% of the living species, among them the dinosaurs .
it Is believed that asteroid was between 10 km and 15 km in diameter , and the probability that a rock of that size hit the Earth it has been estimated at once every 100 million years. Something, however, that it is difficult to verify in our planet, where the vast majority of the craters of more than 600 million years ago of antiquity have been deleted by the erosion , the volcanism and other geological . Therefore, to estimate how many impacts of large meteorites has been in the past of the Earth, the researchers decided to look at the Moon, which has almost no erosion, and where the craters can last for up to times huge.
In this way, the scientists studied the ages of formation of 59 large lunar craters over 20 km in diameter, and also examined the number, distribution and density of the craters side smaller (between 100 metres and one km), formed by the ejection of materials from the 59 craters main.
One of them was Copernicus , a huge crater is 93 km in diameter and account for at least 860 craters side. By examining the density and distribution of these small craters, the researchers were able to determine their age. Using the same method, the scientists found that 8 of the 59 craters analyzed are formed at the same time , something that you did not know and that has profound implications also for the Earth.
The study shows that some 800 million years, which is the age of 8 craters peers, both the Moon and the Earth were hit by a authentic ” rain of meteorites giants “, caused by the rupture of an asteroid much larger.
According to the researchers, it is very likely, given the characteristics of the different families of asteroids known, that the main body of about 100 km in diameter, was a relative of the asteroid of the type C Eulalia , the “father” of a whole pile of debris close to the Earth, and they would be very able to cause a rain of asteroids similar on our planet.
from these considerations, the researchers concluded that the disruption of an asteroid of 100 km to some 800 million years ago had the following consequences: some of the resulting fragments fell on the terrestrial planets and the Sun; others were forming ” families “, as is the case with Eulalia; and the remaining were near-Earth asteroids.