Scientists are trying to confirm that a black rock discovered in Morocco in 2018 left Earth’s attraction, went into space, and then returned to us.
If true, then this rock (officially known as “Northwest Africa (NWA) 13188” [Északnyugat-Afrika 13188]) would be the first meteorite, at least that we know of, to have made this extraordinary tour, reports the Science Alert.
The fact that this 646-gram “boomerang space rock” may have made a sky trip isn’t the only oddity in the story. NWA 13188’s bubbly appearance, crystal texture, and precise chemical composition are strongly suggestive of rocks formed here on Earth from molten minerals produced by volcanoes near subducting oceanic plates.
If we take into account the mixture of oxygen isotopes and trace elements, it becomes highly doubtful that this rock is a meteorite, at least not a typical space rock.
Photo: Jerome Gattacceca. (Public domain image)
According to Jérôme Gattacceca, a geophysicist at France’s National Center for Scientific Research, who presented his team’s findings at the Goldschmidt Geochemistry Conference in France, the rock had an interesting journey, during which it spent a significant amount of time in orbit.
The concentrations of helium-3, beryllium-10 and neon-21 can only be explained by exposure to cosmic rays. This radiation is found in outer space, but is largely blocked by Earth’s magnetic field. Although the concentration of these isotopes was lower than that of other meteorites, it was significantly higher than that of other terrestrial rocks.
This suggested that NWA 13188 had been exposed to galactic cosmic rays for a short but significant period of time, up to a few tens of thousands of years. NWA 13188 also had a glassy “fusion crust,” suggesting that it may have melted as it entered Earth’s atmosphere.
All this “rules out that NWA 13188 is a man-made ‘fake’ meteorite,” write Gattacceca and his colleagues. “Therefore, we consider NWA 13188 to be a meteorite that was launched from Earth and later returned to the same place,” they conclude.
Worth reading:
2023-07-14 20:34:22
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