Space is very much the final frontier for humanity, at least as far as our current understanding of the universe takes us. Only a handful of countries and corporations on Earth have the hardware to readily get there, and even fewer are capable of reaching orbit. For these reasons, working in this field can seem out of reach for many. Nevertheless, there’s plenty about the great expanse beyond our atmosphere that can be studied by the dedicated citizen scientist. With the right equipment and know-how, it’s even possible to capture and study micrometeorites yourself!
For those new to the field, the terms used can be confusing. Meteoroids are small metallic or rocky objects found in outer space, up to around 1 meter in size. When these burn up upon entering the atmosphere, they are referred to as a meteor, or colloquially known as a shooting star. If part of the object survives long enough to hit the ground, this is referred to as a meteorite, and as you’d expect the smaller ones are called micrometeorites, being on the scale of 2mm or less.
Stardust Proves Hard To Find
Being tiny and having fallen from space, micrometeorites present certain challenges to those who wish to find and identify them. In spite of this, they can be found by using the right techniques and a heck of a lot of hard work.
For a long time, micrometeorites were largely ignored by science due to the perceived difficulty in trying to find them. As Verge Science reports, Jon Larsen took this as a challenge. With an estimated 60-100 metric tons falling to Earth every day, Jon simply refused to believe that nothing could be done. Instead, he took a reverse approach at the problem, becoming an expert on all manner of tiny terrestrial particles. Beginning by collecting particles with a magnet, he would painstakingly sort and identify them. By first identifying all the particles of terrestrial origin, it then became easier to focus on whatever was left over to determine whether or not he had found a micrometeorite.
Jon’s work led to much greater interest in micrometeorites worldwide. Now, A project is underway in Berlin to enlist the services of the citizenry to help find these tiny visitors from outer space (Google Translate link). The methodology used is similar to Jon’s experiments but on a grander scale.
The team placed large tarps on the roofs of university buildings and an Ikea outlet. Dust was allowed to settle on the tarps and over time, 100 kilograms of material was collected. This was sifted to extract only particles under 0.8mm, as in the team’s experience most micrometeorites come in under this size range. This also helps to exclude larger particles from other sources, such as dirt and local air pollution. A magnet is then used to select ferromagnetic particles, and these are then washed and prepared for inspection under the microscope. At the end of sorting, only 15 grams was left over from the initial 100 kilograms collected.
At this point, the citizen scientists come in. There currently is no quick solution to the identification of micrometeorites versus terrestrial dust particles; it simply involves grueling and laborious work by humans to inspect and sort the finds. The participants are trained on what to look for, based on previous finds — primarily not-quite-round, darker objects. Once likely candidates are identified, they are sent off for final geochemical analysis to verify their origin.
Having begun in July, the project aims to eventually display some of the finds in the Museum für Naturkunde Berlin. This promises to be its own challenge, due to the size of the objects in question, but it should make for compelling viewing for anyone wishing to see freshly collected stardust in person.
Taking It DIY: Let the Rain Collect Micrometeorites for You!
Naturally, there’s more than one way to go about collecting micrometeorites. While some projects work by placing collection tarps on large roofs, Wayne Schmidt has a nifty method, placing powerful magnets in the downpipe of his rain gutters. As rain washes collected dust off the roof, magnetic particles stick to the magnets as they pass by, allowing them to be easily collected and put under the microscope. Without university-grade equipment, it’s difficult to 100% classify each particle as a micrometeorite or not, but it’s likely a fair few of the handful Wayne has collected are extraterrestrial in origin.
Rich Lund took a very similar tack, mounting neodymium magnets in a ziplock bag, and placing it in a downpipe. After a rainstorm, the collected matter was scattered on a piece of white paper, and several small metallic spheroid objects are visible. While further analysis is likely needed to prove their definitive origin, it goes to show that it doesn’t take a lot of effort to start investigating this at home.
Papers have even been written on the collection of micrometeorites, long thought impractical due to the presence of heavy particulate pollution and human activity kicking up dirt and dust. For those interested in seeing micrometeorites explored with real hardware, the electron microscope images are a real treat. This kind of muscle is what’s needed to verify finds to a scientifically valid level.
It goes to show that this is a fun way to start looking for space rocks that can be done practically anywhere. Obviously, it doesn’t hurt to make friends with your local university’s geology department if you want to get a definitive answer on your finds, but a microscope and a few magnets is all you need to start hunting. Cast your eyes to the skies, and good luck!