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The impact of the meteorite on Earth over the last 500 million years

The impact of the meteorite on Earth over the last 500 million years

The asteroid belt between Jupiter and Mars is the main source of extraterrestrial material that lands on Earth. Credit: ESA / ATG Medialab

For the first time, a unique study conducted at the University of Lund in Sweden traced the flow of the meteorite to Earth over the past 500 million years. Contrary to modern theories, researchers have found that large collisions in the asteroid belt usually did not significantly affect the number of impacts with the Earth.

Researchers are studying 1

9th-century geological series to reconstruct how flora, fauna and climate have changed over millions of years. So far, however, almost nothing is known about the ancient meteor shower – which makes sense because the impact is rare and battered celestial bodies disintegrate quickly when they collide with oxygen on Earth. A new study published in PNAS shows how Lund researchers have restored meteorite bombings to Earth over the past 500 million years.

“The research community previously believed that the flow of a meteorite to Earth was linked to dramatic events in the asteroid belt. However, a new study shows that the flow was instead very stable,” said Birger Schmitz, a professor of geology at Lund University.

To conduct the study, researchers at Lund University’s Astrogeobiology Laboratory dissolved nearly ten tons of sedimentary rocks from ancient seabeds into strong acids, as the sediment contains remnants of meteorites dating back to when they fell to Earth.

Meteorites contain a small part of a mineral, chromium oxide, which is very resistant to decomposition. Chromium oxide microscopic grains were sieved in the laboratory and serve as time capsules with plenty of information.

“Dissolved sludge represents 15 periods in the last 500 million years. In total, we have extracted chromium oxide from almost 10,000 different meteorites. Then chemical analysis allowed us to determine which types of meteorites were grains,” said Birger Schmitz.

Several thousand meteorites land on the Earth’s surface each year, and about 63,000 cosmic rocks have been documented by science. The cosmic rocks originate from the asteroid belt between Mars and Jupiter, where battered celestial bodies from giant collisions revolve around the sun.

“We were very surprised to learn that only one of the 70 largest asteroid collisions in the last 500 million years has led to an increased flow of meteorites to Earth. For some reason, most rocks remain in the asteroid belt. , “says Birger Schmitz.

The study not only destroys generally accepted theories of meteor shower; it also provides entirely new perspectives on which types of celestial bodies are most at risk of colliding with Earth and where they originate in the solar system. From a geological perspective in time, kilometers of celestial bodies collide regularly with the Earth. One such event occurred 66 million years ago, when a celestial body more than 10 kilometers long struck the Yucatan Peninsula. The impact is part of the reason the Earth darkened and the dinosaurs starved to death.

“The future impact of even a small asteroid, for example in the sea near a settlement, can lead to catastrophic results. This study provides an important understanding that we can use to prevent this; for example, by trying to quickly influence the trajectory approaching to the celestial bodies “, concludes Birger Schmitz.

First big look at meteorites from before the giant cosmic collision 466 million years ago

More information:
Fredrik Terfelt et al., Asteroid decay and meteorite delivery to Earth over the last 500 million years, Notices of the National Academy of Sciences (2021). DOI: 10.1073 / pnas.2020977118

Provided by the University of Lund

Quote: Earth’s meteorite impacts over the last 500 million years (2021, June 8) retrieved on June 8, 2021 from https://phys.org/news/2021-06-earth-meteorite-impacts-million-years.html

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