Scott Peterson collecting possible micrometeorites from the Bell's rooftop.

Searching for Stardust

Learn more about the citizen scientist behind our special exhibit


Six or seven years ago, Scott Peterson read an IFL Science article about micrometeorites. “It said you can just go on your roof and anything magnetic would be from the stars,” Peterson says. He found some tiny magnetic particles, and assumed they were micrometeorites. A little while later, he read another article and learned micrometeorites were not only magnetic, but also spherical. Soon after, he found some spherical, magnetic specks he took to be the real deal.

Then Peterson connected with Jon Larsen through his Facebook page, Project Stardust. Larsen is the author of On the Trail of Stardust, and the person to follow if you want to learn about hunting urban micrometeorites.

“I just messaged him pretty much daily until he knew who I was. He actually sent me 10 micrometeorites; then I knew what to look for.” Once Peterson saw these, he realized nothing he had found so far was actually from space. With the proper information, finally, Peterson was encouraged to share his newfound knowledge with other searchers who were similarly misguided. “If I didn’t find John, I’d still have these little things that aren’t micrometeorites and be claiming to all my friends that they are.”

Scott Peterson collecting possible micrometeorites from the Bell's rooftop.

Scott Peterson collecting possible micrometeorites from the Bell’s rooftop.

UMN connection

Armed with accurate identification techniques, Peterson again gathered what he thought were micrometeorites. In 2017, he searched online for a scanning electron microscope and found Anette von der Handt’s website. Von der Handt manages the UMN microprobe lab, and she was willing to help Peterson look at his micrometeorites—but she cautioned him they were likely not the real thing. When he came to the University and Annette fired up the microprobe, though, it turned out that the tiny specks really were from space.

Peterson has been working with von der Handt since then. “It’s a special, rare thing,” he says. When Peterson has enough interesting items, usually every couple of months, he brings a batch into the lab to look at with the microprobe. “It’s a huge machine that shoots electrons onto the micrometeorites, with detectors that read for images, chemical analysis, and elemental mapping,” he says.

Urban findings

There are two categories of micrometeorites. The first is the older sort, often collected at the South Pole because there’s less contamination there and they’re easier to find. These older micrometeorites are also present in sandstone—and they’re from before the industrial revolution, so there’s no worry of “imposters.”

The second category is Peterson’s type of micrometeorites: those found in the city. This sort requires a little more work up front. There’s a lot of debris that can be mistaken for micrometeorites, from road crystals to spheres that are produced by sparking cigarette lighters. Because of this, Peterson and other urban micrometeorite hunters have to go through an extensive cleaning process, first finding the correct size, then weeding out anything with terrestrial origins. Weeding through the material can take a day if Peterson has time, but he usually spreads the task out over a week.

After an hour or two on a roof gathering material, Peterson spends another hour at home sifting through it and drying the product. He gets a little help at this point from his 2-year-old son, who enthusiastically puts the dust into piles and helps clean the sieves. Then Peterson uses ultrasonic jewelry cleaner, sorts through things with a tweezers, and looks at it all on a slide under a microscope.

The work is worth it to Peterson, though. “It’s a rush when you find that micrometeorite, like going to the casino. I kind of zone out when I’m looking at the microscope, then there’s just a jolt of electricity when I find one.” He also loves the fact that with so few people looking for urban micrometeorites, there are many unknowns. “There’s so much science that can come from it, so that keeps me doing it, too. I don’t know necessarily where this can take me, but undoubtedly there’s going to be some amazing stuff that can come from this in the future.”

City Stardust exhibit

Peterson is bringing his findings to the public on his website, and now he has another forum with an exhibit at the Bell. “It’s beyond special to have it here,” he says. “It’s been kind of a dream—we had this idea that it would be possible and now it’s here. It’s an amazing feeling that people are talking about what I do.”

“I really want other people to be able to do this to,” he says. “The more you know, the easier it is, but truly all you need is a magnet and a microscope. I’ve found them in gutters. You can find them in the road—anywhere. Anybody can do it.”