Scientists discover meteorite from the birth of the solar system

Scientists believe they have identified a meteorite that formed in the first million years of our solar system, making it the oldest known meteor of volcanic origin.

The space rock, which began its journey about 4.5 billion years ago, is already an ‘exceptional’ witness for the building blocks of the planets.

The meteorite, known as Erg Chech 002, was discovered in May 2020 by meteor hunters in the Algerian Sahara desert. According to Jean-Alix Barrat, a geochemist at the University of Brest in France, it has remained undisturbed for at least 100 years.

In a recent study published in the Proceedings of the National Academy of Sciences Barrat and his colleagues describe its discovery and several rare features.

There are 43 officially documented fragments, but ‘probably a hundred’, whether in the ground or whatever, the study says. The largest is ‘as big as a fist’, Barrat told AFP.

With its greenish exterior and brownish interior, Erg Chech 002 may not look extraordinary at first glance. But it is in fact extremely rare.

Of the approximately 65,000 meteorites documented so far on Earth, only about 4,000 contain what is known as ‘differentiated matter’. This means that they came from celestial bodies that were large enough to experience tectonic activity.

Of the 4,000 people, 95 percent come from just two asteroids. But Erg Chech 002 is among the remaining five percent.

“It’s the only one out of 65,000 meteorites that looks like it is,” Barrat said.

“Such rocks were quite common at the beginning of the history of the solar system.”

There are two possible explanations for the rarity of Erg Chech 002.

Barrat said that the type of protoplanet from which it originated provides raw material for the growth of terrestrial planets, such as the earth.

Others are pulverized in the great cosmic billiards game about the formation of the solar system.

The moon’s surface, filled with innumerable impacts on asteroids, is a relatively recent witness of this second type of protoplanet.

“No asteroid shares the spectral properties of EC 002, indicating that almost all of these bodies have disappeared, either because they formed the building blocks of larger bodies or planets or were simply destroyed,” the study said.

‘Thrown into space’

The so-called “parent body” of Erg Chech 002 could have measured about 100 kilometers across.

According to the study’s co – authors, March Chaussidon of the Paris Globe Institute of Physics and Johan Villeneuve, a researcher at France’s National Center for Scientific Research at the University of Lorraine, it was formed in the first million years of the solar system.

Metratic meteorites “correspond to the nuclei of protoplanets,” Barrat said.

But Erg Chech 002 is of volcanic origin, meaning it was part of the crust of a protoplanet, rather than its core.

The experts believe that its unique composition was the result of a series of happy events.

On the protoplanet in question, lava must have accumulated on the surface, fueled by the heat of its aluminum core.

The crust containing the meteorite solidified briefly, but – because it showed evidence of sudden cooling – instead of staying on the parent body, some violent force toppled it.

“The rock was thrown into space,” Barrat said.

Further investigation into its composition found that Erg Chech 002 was formed about 4.65 billion years ago.

It traveled through the eyes, “in a gravel shell, protected from solar radiation,” Barrat said.

Then, about 26 million years ago, the rock was pulled loose and continued its journey until it collided with the earth.

© 2021 AFP