Scientists find increase in asteroid impacts on ancient Earth by studying the Moon
An international team of scientists is challenging our understanding of a part of Earth's history by looking at the Moon, the most complete and accessible chronicle of the asteroid collisions that carved our solar system.
In a study published today in Science, the team shows the number of asteroid impacts on the Moon and Earth increased by two to three times starting around 290 million years ago.
"Our research provides evidence for a dramatic change in the rate of asteroid impacts on both Earth and the Moon that occurred around the end of the Paleozoic era," said lead author Sara Mazrouei, who recently earned her PhD in the Department of Earth Sciences in the Faculty of Arts & Science at the University of Toronto (U of T). "The implication is that since that time we have been in a period of relatively high rate of asteroid impacts that is 2.6 times higher than it was prior to 290 million years ago."
It had been previously assumed that most of Earth's older craters produced by asteroid impacts have been erased by erosion and other geologic processes. But the new research shows otherwise.
"The relative rarity of large craters on Earth older than 290 million years and younger than 650 million years is not because we lost the craters, but because the impact rate during that time was lower than it is now," said Rebecca Ghent, an associate professor in U of T's Department of Earth Sciences and one of the paper's co-authors. "We expect this to be of interest to anyone interested in the impact history of both Earth and the Moon, and the role that it might have played in the history of life on Earth."
Earth and Moon impact flux increased at the end of the Paleozoic (DOI: 10.1126/science.aar4058) (DX)
(Score: 2) by RandomFactor on Saturday January 26 2019, @07:03PM
Dreamsicles will no longer have vanilla icecream included and will be 100% orange.
Note - for older readers, this may recall the adulteration of purple/white carrots into the domestic orange abominations of today that were bred by the evil Dutch (House of Orange, basically they liked the color) and used to fool the Nazi's in WW2 into thinking they improved the night vision of allied pilots (vs the reality that they had a new airborn interception radar technology helping them pinpoint incoming bombers.)
Rumor is that we shouldn't be eating orange domestic carrots anymore, but should insist exclusively on heirloom varieties that retain their original non-orange coloration.
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