THE KEY TO FINDING SPACE DUST IS TO FIND OUT WHICH PARTICLES NOT TO PAY ATTENTION TO. I posted here at the beginning of this year about how a nonscientist, John Larsen, had collected about 500 micrometeorites from gutter sediment from the roofs of buildings in Oslo and other cities. This article in the New York Times (March 10) by William J Broad tells more about Larsen, who has a book, IN SEARCH OF STARDUST: AMAZING MICRO-METEORITES AND THEIR TERRESTRIAL IMPOSTERS, coming out in August. The article has photographs of nine of Larsen’s finds.
The key to Larsen’s discoveries was his analysis of what particles to disregard. It had been thought urban areas were not good places to look for micrometeorites because of all the human contaminants. Searches were conducted in Arctic areas instead.
Larsen conducted his searches by the general appearance of the micrometeorites and postponed paying attention to chemical composition of the particles until he had narrowed the number of possible space particles. A scientist who has worked with Larsen says that: “Larsen has done a valuable thing in classifying the contaminants.”