The century-long hunt for the gigantic meteorite that vanished

A soldier returned from the Sahara desert in 1916 with a wild story about a meteorite that dwarfed all others. Over 100 years of hunting yielded nothing – but now twin brothers think they have solved the puzzle

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The century-long hunt for the gigantic meteorite that vanished

A soldier returned from the Sahara desert in 1916 with a wild story about a meteorite that dwarfed all others. Over 100 years of hunting yielded nothing – but now twin brothers think they have solved the puzzle

By Alex Wilkins

30 December 2025

[New Scientist. Science news and long reads from expert journalists, covering developments in science, technology, health and the environment on the website and the magazine.]

Julien Pacaud

It all started with an overheard conversation between some camel herders. The year was 1916, and Gaston Ripert, a French army captain, had been injured and sent to recover in the small town of Chinguetti in Mauritania. It was a lonely, dusty place on the edge of the Sahara. So when Ripert heard local people talk of a colossal block of iron out in the undulating expanse of dunes, he was intrigued. They referred to it as the “iron of God”.

He persuaded one man to guide him to this fabled iron and what followed has passed into legend. After an arduous overnight camel ride, Ripert arrived at what appeared to be an enormous metal edifice – some 100 metres wide in his estimation – partly buried in the dunes, its side polished by the sand to a mirror finish.

Ripert brought back a piece of rock from the site, and when it was analysed after the war, it was found to be genuine meteorite. That caused a sensation and prompted meteoriticists the world over to wonder if the iron of God itself could also be from space. If so, it would be an astonishing find, a meteorite far more massive than any found before.

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Over the past century, a rotating cast of adventurers, scientists and treasure hunters attempted to retrace Ripert’s footsteps, but all came back empty-handed. Hope of success was ebbing away. But in the past few years, two identical twins – one an astrophysicist, the other an engineer – have taken up this challenge. “As far as anyone knows, this meteorite could exist,” says Stephen Warren. “It could be under a sand dune.” And thanks to the twins’ work, we may now be as close as we have ever been to finding the truth.

The legend of the “iron of God”

Meteorites have fascinated humans for centuries, with some ancient cultures venerating and even worshipping them. Modern scientists are just as captivated, because, as well as being objects of wonder, meteorites can reveal the deep history of our solar system. They come in all sizes, from tiny specks of cosmic dust to boulder-sized rocks. The largest known single piece of space rock on Earth today is the Hoba meteorite, which is about 2.7 metres wide and still lies where it fell in Namibia. That is partly why Ripert’s tale inspired such interest: his iron of God would have been thousands of times larger.

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From the start, his story had an aura of mystery around it. The man who agreed to take Ripert to see the iron, one of the local village heads, did so on the condition that he kept the location secret. Ripert later wrote that they travelled “blind”, which has been interpreted to mean he had no map or compass and was perhaps blindfolded. They travelled overnight by camel for 10 hours, arriving at the fabled rock as a new day dawned. By the first shards of morning light, Ripert saw a vast cliff face that was 40 metres high, 100 metres long and “strongly polished by windblown sand”, as well as a longer side that had been buried under the dunes, making its third dimension “impossible to estimate”.

There are scientific reasons to think this is more than just a story. Ripert examined the huge iron closely and described seeing “metallic needles sufficiently thick so that I could not break them or remove them”. These needles later became an important and puzzling piece of the mystery, because what Ripert described sounds eerily similar to real observed properties of a rare class of meteorites called mesosiderites. These meteorites are made of iron encased in a delicate layer of silicate mineral. This means that after a long period on the ground, the mineral layer gets eroded, leaving needles of the hardier metal. This was discovered long after Ripert’s journey into the desert, so it isn’t a detail he could have intentionally fabricated.

[Part of the Chinguetti meteorite]

Gaston Ripert brought back with him a meteorite from Chinguetti. It has now been split into pieces – this one is kept at the Smithsonian National Museum of Natural History

Chip Clark/Smithsonian National Museum of Natural History (NMNH)

And there’s an even stronger piece of evidence for the story’s veracity. Ripert said he climbed on top of the iron mass and there found a smaller rock. He brought this back with him, and in 1924 it was analysed and confirmed to be a meteorite by the mineralogist Alfred Lacroix at the French Academy of Sciences in Paris. It turned out to be a mesosiderite, which adds weight to the story of the strange needles. This, coupled with testimony of Ripert’s honourable character from friends and colleagues, meant that scientists at the time were captivated by the finding and had little doubt that the larger meteorite existed. Lacroix, when presenting the finding, said: “If, in effect, the dimensions given by M. Ripert are exact, and there is no reason to doubt them, the metallic block constitutes by far the most enormous of known meteorites.”

Lacroix divided the smaller meteorite into fragments for analysis, and today the largest piece is kept in the collection of France’s National Museum of Natural History. It takes only a quick glance at this specimen to see why Ripert would have immediately noticed the rock. There are large, shiny chunks of what look to be pure metal surrounded by tiny clumps of irregular rock. This feature is a consequence of how scientists believe mesosiderites form, where one asteroid smashes into the pure iron core of another.

The priest of the Sahara

A meteorite the size of a building shimmering in the sun would be a magnificent sight, and it wasn’t long before scientists began asking a simple question: where was it? Ripert’s notes from the trip, which were passed to Lacroix, gave scant information on its location, understandably enough, given that he was travelling blind. Ripert did estimate it was 45 kilometres south-west of Chinguetti and just to the west of a local water hole. The captain had led a camel corps during the first world war, and knew the position of the sun, so these clues at first seemed reliable. But the first people who went looking for the treasure in the desert came back with nothing to show for their trouble. And when astronomers then began communicating with Ripert by letter, his story seemed to shift. The direction may actually have been south-east, he wrote, and the meteorite could now be buried by migrating dunes.

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*Original source*