It is estimated that anywhere from 37,000 to 78,000 tons of meteorites hit Earth’s surface each year. That might seem a bit high, but the vast majority of this figure is made up of micrometeorites, which are dust-sized specks about 50 µm to 2 mm in diameter. It is estimated that about one micrometeorite lands every square meter per year. This means that there are probably loads of micrometeorites right outside your door! Jon Larsen of Project Stardust is an advocate for all citizens going out and finding micrometeorites.
The hunt for micrometeorites begins with using a good magnet. Don’t just grab something off of your refrigerator, purchase a magnet that is extremely strong—like the neodym magnet pictured—that has a hook to be used as a handle. The stronger the magnet, the more likely you are to pull samples off of the ground. Of course, with a magnet that strong seeking out these tiny micrometeorites, it will be very challenging, if not impossible, to pull them off if they make direct with one another, which could also contaminate the samples between locations.
Create a barrier between the magnet and the samples by using ziplock sandwich bags. Because the magnet is going to be dragged across the ground, the sandwich bag might become damaged or torn by sand and rocks on the ground. Using two layers of bags is recommended, and have extras on standby in case replacements are needed when out hunting. The layers of sandwich bag should be held tightly around the magnet, in order to have the best result.
Now that the magnet is properly protected, search for micrometeorites by dragging it along the ground. The tiny particles you are hunting will not be able to travel toward the magnet and will need to be contacted directly. If soil is wet, it will be harder for the magnetic particles to be pulled away from the substrate. Stick to searching dry areas, or take a sample of soil home, allow it to dry, and then use the magnet to try to find micrometeorites.
Once the surface of the magnet is covered with particles, pull out a third ziplock sandwich bag to empty them into. The hand holding the magnet/sandwich bag/magnetic particles should go into the opened third bag. Separate the magnet from the dual sandwich bag layer that had been protecting it, which will remove the magnetic force on the particles, and allow them to fall to the bottom of the bag for collection.
Be sure to mark the bag with the location, date, and any other relevant information about that hunting trip. After a trip has been completed, weigh the bag of raw samples, and record the result. If you plan to go micrometeorite hunting more than once, it will be very useful to start a personal database so all samples can be coded with the information. This will make it much easier to recall the data later when comparing samples between different hunts in different locations.
Begin processing the samples by using sieves. Multiple sizes should be used, starting with mesh that has openings of about 1.5 mm, down to one with 0.4 mm openings. Bits of glass and other materials may get stuck in the sieve over time, which could necessitate replacements in the future.
Once the samples have been sieved and sorted, you can begin exploring them with a microscope. The particles you are seeking will mostly be spherical (check out header image above), so you can use a toothpick or other nonmagnetic tool to sort through the pieces under the microscope. Separate the spherical pieces from other particles that could be manmade, or at least terrestrial. Once those pieces have been separated, put them in containers marked with codes from your personal database so they can be examined later. You could also keep a written log in order to keep notes and drawings about the samples for later reference. A good USB camera will be needed to take pictures of samples in order to share your findings with other micrometeorite enthusiasts.
You may also be surprised at what can be found just from cleaning out your gutters! Put all of the material into a bin, and use dish soap and hot water to separate the magnetic particles from anything they might have been stuck to. Use a sieve to begin separating the leaves and sticks, until a magnet can be used (with the same sandwich bag technique as before) to pull any magnetic particles out from the dirt. Collect, catalog, analyze, and store the samples, just as described above.
All photos belong to Project Stardust - Jon Larsen. Be sure to check out Larsen’s site and learn more about collecting micrometeorites. Make some new friends and start comparing your samples from those found around the world today!