2023-07-29 19:00:19
Meteorites fall on Earth every day. But meteorites that come from our own planet are much less common! Moreover, if the analyzes of French researchers are confirmed, the one found in Morocco would be the first known boomerang meteorite.
In 2018, meteorite hunters discovered a piece of pebble weighing just under 650 grams in the Sahara Desert, Morocco. No one had seen him fall to Earth. But it is not impossible that it was moved once or several times by nomadic peoples living in the region. The first analyzes, they, suggested that it could be a volcanic rockvolcanic rock. Not much to report, then.
Until some specialists in the study of meteorites from the University of Aix-Marseille decide to take a closer look. Initially, just because this rock was ” odd “. And on the occasion of the Goldschmidt 2023 Conference, an international geochemistry conference held a few days ago in Lyon, the researchers presented their results. According to which NWA 13188 — for Northwest Africa 13188 — would ultimately be quite exceptional. This would be the very first boomerang meteorite. A terrestrial meteorite, then.
Did you know ?
In 2019, researchers identified in a sample of the Moon brought back to Earth by the Apollo 14 mission, tiny fragments of quartz, feldspar and zircon. Fragments probably all originating from our planet. The researchers suggested that this piece of rock could have been ejected from our Earth when the Moon was much closer to our planet, billions of years ago. It would then be the first terrestrial meteorite found.
A terrestrial meteorite? Yes. A rock formed on Earth and expelled into space where it would have potentially spent millions of years before falling back to our planet. In a cosmic boomerang game.
A meteorite, no doubt, but is it terrestrial?
Among the clues that suggest that NWA 13188 is a terrestrial meteorite, there is first the fact that it effectively concentrates all the characteristics of a volcanic rock. So much for the land side. Then there is the “crustcrust” which covers it. A thin layer of rock that has visibly been subjected to thermal shock. The sign that it burned up entering the Earth’s atmosphere. A thin layer that is not found on the volcanic rocks that have remained on our planet. Only on pebbles from space. So that’s also for the meteorite side
There are also a few isotopes — such as beryllium-3, helium-10 and neon-21 — that suggest the rock has been exposed to cosmic radiation. For a fairly long period of time. At least 10,000 years old. And so this is how the boomerang terrestrial meteorite theory came about.
The researchers explain that a massive eruption could have directly ejected the rock into space. But there is no trace in the geological records of an eruption powerful enough for that. Even the recent record-breaking eruption of the Hunga Tonga-Tunga Ha’apai submarine volcano couldn’t send rocks high enough. It thus seems more likely that the rock was catapulted during a large collision with an asteroidasteroid.
But all this remains to be confirmed. The work of researchers from the University of Aix-Marseille has not yet been validated by peers. And some believe that the rock could well have been formed elsewhere in our Solar System, while showing similarities to terrestrial rocks. Especially since for the time being, the supposed boomerang meteorite could not be dated and linked to a particular impact crater. This is the task to which the French team now intends to tackle.
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