Who among us doesn’t thrill to catch a glimpse of a meteorite streaking across the night sky? Except for a few colorful cases — a living room in Connecticut, an explosion in the sky over Chelyabinsk, Russia — these beauties disappear into our atmosphere. They’re just a small fraction of the objects that hit the earth — scientists estimate that some 4,000 tons of them arrive yearly. Some are so tiny they don’t even fall: They just float down. So where is all this stuff? Researchers have found micrometeorites — which are typically smaller than width of a human hair — in Antarctica and other remote locations. Now a new picture book, In Search of Stardust: Amazing Micro-Meteorites and Their Terrestrial Imposters, reveals that, really, it’s everywhere.
The author of the book, amateur scientist Jon Larsen, has coauthored an article in Geology with Imperial College earth and planetary science lecturer Matthew J. Genge and two of his students, Martin D. Suttle of Imperial College and Matthias Van Ginneken of the Université Libre in Brussels. In the article, they reveal that this “cosmic dust” can be found most anywhere — most of the photos in the book come from flecks collected from house gutters in Norway. The cosmic stuff is so ubiquitous that we probably eat it in our salads all the time.
The article and book are the products of Larsen’s Project Stardust. It began, he tells the New York Times, when he noticed something sparkling on an outdoor table he was cleaning off: “It was blinking in the sunlight. It was angular in some way, kind of metallic but so small — a tiny dot.” The fleck intrigued him and, suspecting it came from the sky, he started collecting all sorts of stuff he thought that might be extraterrestrial. Larsen is a successful jazz guitarist, and so he had ample opportunity to take samples in all sorts of places during his travels: roads, parking lots, grooves, drains, gutters, and park benches. “Still, I didn’t find a single micrometeorite” — including that original tabletop fleck — “It was very frustrating.”
He decided to approach his search from the opposite direction. Instead of trying to identify bits from space, he would instead teach himself to recognize the terrestrial source of all the samples he collected. He could reasonably assume that anything left over might actually be a decent space-debris candidate.
About two years ago, Genge was able to confirm that a speck Larsen had collected from Norway was indeed space dust. That was all it took: “Once I knew what to look for, I found them everywhere.” Larsen views his process as ““something that anybody can do. It could and should become part of teachings in schools, an aspect of citizen science.” The key is knowing what to look for.
The paper’s conclusions are being endorsed by astronomers such as University of Washington astronomer Donald E. Brownlee, and by extraterrestrial materials scientist at the Johnson Space Center in Houston Michael E. Zolensky, who found some space particles on the roof of a building containing moon rocks with Larsen. “It was pretty cool,” Dr. Zolensky told the Times. “The curation building is now a collector of cosmic dust.”