Micrometeorites – tiny remnants of shooting stars – turn out to fall everywhere on Earth, even right in the middle of urban areas. Research by planetary scientist Guido Jonker shows that these barely visible particles are not only surprisingly accessible but also contain crucial information about the history of our solar system.
The grains are extremely small, often no larger than a grain of sand and sometimes even thinner than a human hair. As a result, they are difficult to distinguish from grains of terrestrial and human origin. It was precisely this challenge that led scientists in the past to reach divergent conclusions regarding the composition and quantity of cosmic material reaching Earth.
Constant influx
By developing new methods that minimize errors in collection and analysis, it has now become possible to reliably compare micrometeorites from different regions and time periods. This reveals a remarkably clear picture: the influx of cosmic dust to Earth appears to have remained virtually constant for millions of years. The materials from which these particles are composed have also been better established, which helps researchers reconstruct the development of the solar system more accurately.
A second major breakthrough is where these micrometeorites can be found. For a long time, it was assumed that urban environments were unsuitable due to the large amount of sand and human pollution. Researchers therefore focused primarily on remote areas such as polar regions. However, that view has since proven to be outdated. With improved techniques, micrometeorites can also be detected in cities – and even in large numbers. For instance, a single rooftop has already yielded more than a thousand specimens.
Citizen Science
Research into micrometeorites is ideally suited for citizen science. Interested individuals can contribute to the collection and analysis of cosmic dust themselves using relatively simple tools, such as a microscope and a lot of patience. This makes science more accessible and fosters growing collaboration between professionals and amateurs. “The implications are significant: not only will researchers gain a more reliable picture of our solar system, but it will also become clear that the universe is literally part of our immediate living environment. What once seemed far away turns out to be simply all around us,” says Jonker.