Researchers have found the oldest meteorite collection on Earth, in the driest desert on the planet

Meteors hit the Earth pretty much constantly and you can find their ancient remnants everywhere, from King Tut's grave to a guy's farm in Edmore, Michigan. But to better understand where these space rocks come from and how long they live as terrestrial expats, it's worth visiting the densest meteorite collection on the planet – and this is found in the Atacama Desert. in Chile.

How is Atacama so special? For starters, it's old – over 15 million years – and that means that meteors that have crashed on its 130,000 square kilometer surface have the opportunity to be as very old. This is a geological advantage over other deserts, including Antarctica, which is overflowing with meteorites, but is generally too young to accommodate more than half a million space rocks. years, according to Alexis Drouard, researcher at Aix-Marseille University of France and senior author of a new study in the journal Geology. [In Images: Stunning Flower Fields of the Atacama Desert]

Drouard and his colleagues recently embarked on a meteorite-hunting trip in the Atacama Desert in hopes of finding a range of rocks spanning millions of years. "Our goal in this work was to see how the flow of meteorites to the Earth changed on a large scale," Drouard said in a statement. In other words, could the Atacama space rocks be revealed when the Earth was bombarded by meteorites more or less frequently?

For the new study (published May 22), researchers collected and studied nearly 400 meteorites, analyzing both the age and chemical composition of alien stones. According to the advanced age of the desert, about 30% of meteorites were more than a million years old, while two of them had accumulated dust for over two million years. 39; years. According to Drouard, it is the oldest collection of meteorites on the surface of the Earth.

And as for the flow of meteorites? The team extrapolated the results of its small sample to determine that the impact activity has remained relatively constant over the past 2 million years, reaching about 222 meteor impacts on 1 km2 of desert per square kilometer.

Surprisingly, the composition of meteorites has changed more dramatically. According to the researchers, the meteorites that bombed Atacama a million to half a million years ago were significantly richer in iron than the rocks that fell before or after. It is possible that they all come from a single swarm of stones that has detached from the asteroid belt between Mars and Jupiter, the team wrote.

Originally published on Science live.