This story appears in the August 2017 issue of National Geographic magazine.
A Norwegian jazz musician and citizen scientist, Jon Larsen has figured out how to do something the experts thought was impossible—find specks of cosmic dust, called micrometeorites, amid the detritus of human habitation. Scientists look for these particles, which rain down constantly on Earth, in Antarctica and other pristine locations, but Larsen thought there should be a way to collect them in more populated places.
Some micrometeorites are real stardust—flecks from exploded stars. Others are likely created when asteroids collide and comets vaporize. Larsen learned to identify the unique features that take shape as the specks plummet through Earth’s atmosphere, first melting and then solidifying. The examples shown here—from Larsen’s new book, In Search of Stardust—exhibit swirling ridges, golden spots of iron-nickel metal and sulfide, and crystal pyramids of minerals, which formed during the journey.
Larsen was able to find micrometeorites by washing the sludge that had accumulated in open roof gutters, sifting it, and then using a magnet to extract particles from the remaining grit. After approaching many scientists, he finally persuaded Matthew Genge, a planetary scientist at Imperial College London, to examine 48 particles he had collected. Genge analyzed their composition and confirmed that Larsen had indeed managed to find extraterrestrial dust amid earthly debris. “Jon was the one staring down the microscope,” says Genge, “going through hundreds of thousands of particles to find just one micrometeorite.”