Tiny but beautiful meteorites fall to Earth every single day – here’s how to find them

I climbed up the long ladder, hands cold on the metal, and pulled myself up onto the sprawling asphalt roof of a warehouse. Jon Larsen had gone up first and stood, grinning, as a slight drizzle began to fall. I had come here to the outskirts of Oslo to join Larsen in the pursuit he founded: urban meteorite hunting.

The journey that led me to this moment started years ago when I was at a scientific conference about the history of the solar system. As a science journalist, I spend a good amount of time at such conferences, and they are nearly always wonderful, mind-expanding affairs. At this one, to my surprise, the scientists spent a lot of time talking about meteorites and how they were time capsules from the birth of the solar system. I left with two questions tumbling in my mind. How does one go about finding meteorites in the first place? And, once you have one, how do you read and interpret the subtle geological evidence inside?

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Finding the answers was a wild ride and it resulted in my book, The Meteorite Hunters. I met many fascinating characters along the way, but it was perhaps Larsen who captured my imagination most of all.

His first love was jazz. Indeed, Larsen is probably Norway’s most famous jazz guitarist and founded the string quintet Hot Club de Norvège. But it was a bright, otherwise typical morning in 2009 that the second all-consuming passion of his life found him. While Larsen was having breakfast outside, a speck of dust fell on his clean, white table and it got him wondering: could this possibly have come from space? Logging on to the internet, he learned a new word: micrometeorite.

It turns out that scientists have long known dust from space falls to Earth in huge amounts – an estimated six tonnes every day. The trouble is, it can only ever be found in the most pristine areas, like Antarctica, because in most places there is so much other dust that micrometeorites are immediately lost.

But Larsen wasn’t having that. Over the following decade, he developed a tried-and-tested method for harvesting space dust, which eventually resulted in him publishing a scientific paper in 2017 detailing 500 of his finds. We followed this method during my visit to Oslo. The first step is to collect as much muck and grime as you can from an urban rooftop, which is what Larsen and I did up there on top of that warehouse.

I have to admit my role was perfunctory; I held the bin bags open while he shovelled in the dirt. We worked quickly – rain makes the dirt very heavy – so everything went in, including bits of rubbish and old bird bones. Then we chucked the bulging plastic bags over the side of the building and climbed back down. 

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Then begins Larsen’s process of successively washing, sieving, separating out the grains of dust into fractions. One trick is to use a magnet, because many micrometeorites contain a fleck of iron. The final step is to go through the cleaned-up dust grain by grain under a microscope. It’s by turns dirty and painstaking work. But the following evening I saw for myself why it is so worthwhile: the tiny meteorites that Larsen finds are unutterably beautiful.

Larsen struck up a friendship with a geologist and optics expert named Jan Braly Kihle, who developed a customised photography set-up that snaps extreme close-ups of Larsen’s finds. The evening after our rooftop adventure, in Kihle’s basement, I watched as a succession of tiny wonders were revealed on his computer screen.

These days, Larsen can interpret the different colours and strange, streamlined shapes of each micrometeorite to reconstruct the story of it spinning and melting as it plummeted at searing speed through our atmosphere. And because he has been doing this for so long now, and has thousands of specimens, Larsen has also begun to find rare micrometeorites. Those include, for instance, scoriaceous micrometeorites, which have somehow fallen through the atmosphere without fully melting.

I’ll never forget my time hunting micrometeorites with Larsen. And that’s partly because of what I came to understand about the significance of what he collects. Regular-sized meteorites are chunks that have broken off asteroids, which are material formed in the solar system’s youth that never got big enough to become a planet.

But micrometeorites are not just shavings from meteorites – rather, they are the leftover dust that never formed into anything larger in the first place. In that sense, they are about the most pristine material you can find in our solar system, a sample of the primordial powder from which everything, including us, was ultimately made.

Joshua Howgego is an editor at New Scientist magazine. 

The Meteorite Hunters by Joshua Howgego is out now (Oneworld, £18.99), You can buy it from the Big Issue shop on bookshop.org, which helps to support Big Issue and independent bookshops.

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