Source: theguardian.pe.ca, Published: March 10th, 2021
Researchers have discovered a 4.6 billion-year-old meteorite rock in the Sahara Desert, that they say once belonged to a long-lost baby planet that never made it to adulthood.
The meteorite may be the oldest rock ever analyzed, scientists wrote in a study published in the journal Proceedings of the National Academy of Science, and perhaps the one of the few remaining evidence of the solar system’s planetary ancestors.
“I have been working on meteorites for more than 20 years now, and this is possibly the most fantastic new meteorite I have ever seen,” said Jean-Alix Barrat at the University of Western Brittany in France.
The rock, named Erg Chech 002, was discovered in May 2020 in the Erg Chech area of southwestern Algeria.
Scientists immediately identified the rock as unusual. Unlike most discovered meteorites, which are made of basalt — created after lava has cooled off, the meteorite seemed to be composed of a different, much rarer volcanic rock called andesite.
It was classified as an achrondite, the research paper stated. Achrondites are igneous rocks — made from molten magma — that come from a body that has undergone internal melting that distinguishes the core from its crust.
Only 3,179 achrondites have so far been identified, according to the Meteoritical Bulletin Database, 75 per cent of which have originated in the crust and mantle of the asteroid 4 Vesta in the asteroid belt within the solar system, researchers reported. As they usually come from only one or two planetary bodies, they can reveal very little about the diversity of the solar system’s planetary history.
However, this andesitic achrondite, according to Barrat was different from any other meteorite that has ever been found. Chemical analysis of the rock found that it was once molten and had solidified around 4.6 billion years ago.
The Earth is 4.54 billion years old.
“This meteorite is the oldest magmatic rock analysed to date and sheds light on the formation of the primordial crusts that covered the oldest protoplanets,” the researchers wrote in their paper .
Previous studies have found that such silica-infused andesite crusts were likely common during our solar system’s protoplanet-forming stage, “contrary to what the meteorite record suggests,” the researchers wrote.
But any efforts to find a comparable example were to no avail. Andesitic rock, they say, is not only rare in the meteorite record but also in the asteroid belts within the solar system.
Scientists concluded that the rock must be a remnant of a long-lost protoplanet, a primordial planet that was in its early stages of formation.
EC 002 may be the only remaining evidence of its protoplanet, the study reports. Other relics of the planet’s ancestors may have either been smashed to bits or crashed to form other rocky bodies.
Some may have even combined to form the first building blocks of Earth, researchers posited.
“When you go close to the beginning of the solar system, it’s more and more complicated to get samples,” Barrat said . “We probably will not find another sample older than this one.
Copyright Postmedia Network Inc., 2021
