'Boomerang' meteorite might be the first known Earth-origin meteorite
Scientists have made an intriguing discovery that could potentially reshape our understanding of meteorites. Unearthed in the Sahara desert of Morocco a few years ago, a dark reddish-brown stone is believed to be a remarkable specimen – a meteorite that was once flung from Earth into space, only to return thousands of years later, remarkably intact.
Presented at the Goldschmidt geology conference in Lyon earlier this month, this unusual rock, officially known as Northwest Africa 13188 (NWA 13188), has captured the attention of geologists worldwide. Early diagnostic tests reveal that the rock's chemical composition aligns with volcanic rock on Earth, however, some of its elements have undergone changes that typically occur when interacting with energetic cosmic rays in space—providing compelling evidence of its extraterrestrial journey.
The measured concentrations of these altered elements, known as isotopes, are too high to be accounted for by Earth-bound processes, leading researchers to believe that the rock was propelled into space by an asteroid impact around 10,000 years ago. Though volcanic eruptions can also send rocks soaring, geologists argue that such an event is unlikely to explain this particular meteorite's characteristics.
"I think there is no doubt that this is a meteorite," Frank Brenker, a geologist at the Goethe University Frankfurt in Germany who was not involved with the new study, said according to Space.com. "It is just a matter of debate if it is really from Earth."
During its voyage beyond Earth, NWA 13188 would have encountered galactic cosmic rays, leaving behind distinctive isotopic imprints. The rock's glossy, melted surface known as a fusion crust—formed as it raced through Earth's atmosphere upon re-entry—further supports this extraordinary journey.
Purchased by Albert Jambon, a retired French professor, in 2018, the 1.4-pound NWA 13188's origin remains somewhat mysterious. Believed to have been acquired from nomadic Bedouin tribes in the Sahara, the exact landing site after returning to Earth is unknown.
"I purchased this one just because it was odd," Jambon said. "Nobody knows what this stone is really worth."
Although the discovery team is convinced of NWA 13188's uniqueness, other geologists remain cautious, calling for further investigation before making extraordinary claims. Determining the rock's age and identifying a suitable impact crater on Earth that fits the timeline are among the critical challenges.
If confirmed, NWA 13188 will mark the first documented instance of a "boomerang meteorite," a remarkable feat that could open new avenues of research. So far, a tiny chunk of Earth discovered on the moon by Apollo astronauts in 1971 stands as the only confirmed member of this intriguing category.