A fascinating discovery has been made in regards to a dark reddish-brown stone that has scientists thinking it may be the first-ever boomerang meteorite.
Named Northwest Africa 13188 (NWA 13188), the rock was found in the Sahara desert in Morocco, and has since been referred to as a boomerang meteorite over beliefs that it once left and then returned to planet Earth.
"I think there is no doubt that this is a meteorite," said Frank Brenker, a geologist at the Goethe University Frankfurt in Germany, who was not involved with the new study. "It is just a matter of debate if it is really from Earth."
Early tests conducted on the meteorite show it has a chemical composition similar to volcanic rocks found on Earth. However, some of its elements have been altered into lighter forms, which can only occur when exposed to cosmic rays in space. These altered elements provide evidence the rock traveled beyond Earth's atmosphere.
The concentration of these lighter elements, known as isotopes, is too high to be explained by processes occurring on Earth, according to Jérôme Gattacceca, a geophysicist leading the investigation of NWA 13188. Researchers suspect the rock was initially launched into space by an asteroid impact approximately 10,000 years ago.
Although volcanic eruptions can also propel rocks to high altitudes, geologists believe this is unlikely to explain these findings, as even the largest volcanic eruptions fall short of reaching Earth's atmosphere.
Once in space, the meteorite would have been exposed to galactic cosmic rays, high-energy particles that originate from exploding stars. These cosmic rays bombard meteorites and leave behind telltale isotopic imprints.
In the case of NWA 13188, the levels of these elements are higher than in any Earth rock but lower than in other meteorites, suggesting the rock spent some time in orbit around Earth before re-entering the atmosphere.
Another clue indicating the rock's journey to space is a glossy melted surface known as a fusion crust, which forms when meteorites pass through Earth's atmosphere. NWA 13188 possesses this distinctive feature.
Further research is needed to confirm the rock's origin and its journey in space. If verified, this boomerang meteorite will provide valuable insights into the complex dynamics of objects moving between Earth and space.
The findings of the study were presented at a recent Goldschmidt 2023 Conference but have not yet been published in a peer-reviewed journal.