How space rock hunters found these rare traces of a meteorite in Sweden

How space rock hunters found these rare traces of a meteorite in Sweden
This fragment is about three millimetres long. Photo: Natural History Museum
Swedish meteorite hunters have discovered fragments from the fireball meteor which lit up the night sky in November, the first from an observed meteorite found in Sweden since 1954.

Jörgen Langhof, a minerologist at Sweden's Museum of Natural History, found and analysed several of the fragments, after an anonymous hobby meteorite hunter tipped him off to the location.

“It's very interesting because fragments from iron meteorites are quite rare,” he told The Local. “They are very sensitive to weathering. If there's water and weak acids in the ground it will decompose in smaller particles and in time dissolve completely.”

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The last time fragments of an observed meteorite were found in the country was back in 1954, when a stone meteorite hit the ground just a few metres away from a group of young farm workers. No fragments of an observed iron meteorite have ever been found in the country.

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The hobby meteorite hunters found the location after Eric Stempels, an astronomer at Uppsala University, who runs a network of cameras recording meteorite activity, calculated from the footage that the meteorites from the bolide, or fireball, observed in November, should have hit the earth around the village of Ådalen in Enköping.

He then called on amateur meteorite hunters to comb the 16 square kilometre area.

“When a meteor meets the earth's atmosphere (…) the heat that arises melts the surface and usually the meteorite melts away completely,” he said in a press release.

“If the meteor is large enough, parts can survive the violent journey through the atmosphere, and the remains can then be found on the ground in the form of meteorites.”

The landing site was found when one of the hunters spotted a large tree root which appeared to have been severed, and later identified a large boulder next to it, which appears to have been hit first.

“It was very lucky that this meteorite hit the rock first,” Langhof explained. “If it hits soft ground, an iron meteorite will be buried four or five metres down, and you won't find it afterwards. It's gone.”

When Langhof arrived at the scene, it didn't take long for him to find his own fragments.

“I was walking in the blueberries just about five metres from the rock. I had a really strong neodymium magnet, with a little string, so I couldn't swing it around, and after five minutes, I collected some fragments of up to five or six millimetres.”

The museum's analysis confirmed that the fragments were from the meteorite, and estimated that they comprised about 90 percent iron and about 10 percent nickel, typical of an iron meteorite. 

Dan Holtstam, who is responsible for the museum's mineral collection, said in the press statement that the museum was hoping to find more fragments to enable it to carry out a more thorough analysis.

But Langhof said it was uncertain whether any remaining fragments would have survived the winter.

“Now there is snow here and I think in spring or summer that it will be very tricky to find more fragments with a magnet, because they will rust and fall apart.” 


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