The bulk of the objects whizzing around our solar system originate in places other than our planet. But a group of scientists believe they’ve found a truly unique item — a “boomerang meteorite.”
In case you don’t speak astrophysicist, a boomerang meteorite is a space rock that originated on Earth, spent a holiday traipsing around the solar system, and then, amazingly, returned.
Turned up in Sahara
According to Live Science, meteorite hunters found the 646-gram object — dubbed NWA 13188 — in the Sahara in 2018. Subsequent analysis by scientist Jerome Gattacceca and his team from Aix-Marseille University revealed the meteorite’s fascinating properties.
The composition of the NWA 13188 indicates that it was from Earth, but a fused crust on its outer surface suggests it experienced the kind of heat treatment you only get if you blast back into our atmosphere from the cold reaches of space.
The team also reported that they found certain isotopes in NWA 13188 suggesting that this little chunk of terra firma has been zipping around out there for 10,000 years or more.
But how does a piece of Earth get ejected into the atmosphere in the first place? It could be a catastrophically large volcanic eruption. However, there hasn’t been a volcanic eruption on record powerful enough to launch rocks beyond the Earth’s gravitational field and into the depths of space. So this is the least likely explanation.
Could a catastrophically powerful volcanic eruption have ejected the meteorite into space to begin with? Unlikely, say scientists. Photo: Shutterstock
A more realistic origin story would be if a large asteroid smacked into the Earth at around that time, dislodging material and ejecting it into space. That is the likeliest scenario.
If the findings bear out, NWA 13188 will be the first and only known terrestrial meteorite.
Controversy
It’s important to note that the findings, presented at a geochemistry conference in Lyon, France, aren’t peer-reviewed and have not been published in a journal. This has prompted some scientists to express skepticism.
“It is an interesting rock,” Ludovic Ferriere told Space.com. Ferriere is a curator of the meteorite collection at the Natural History Museum Vienna in Austria and was not involved with the initial analysis. But he’d prefer “more investigations to be conducted before making extraordinary claims.”
“I think there is no doubt that this is a meteorite,” Frank Brenker, a geologist at the Goethe University Frankfurt in Germany, also told Space.com. Like Ferriere, he was also uninvolved with the work on NWA 13188. “It is just a matter of debate if it is really from Earth.”
The best way the Aix-Marseille University team can prove their claim is to locate an impact crater and match the composition of NWA 13188 to rocks in the surrounding area. Further analysis to determine the precise age of the rock will also be helpful.
In the meantime, the story of NWA 13188 serves as a reminder that what goes around comes around — especially where orbital physics is concerned.
