Search for Micrometeorites when Cleaning Your Gutters

Micrometeorite Images
Image Credit: A display of nine of the most spectacular micrometeorites from Jon Larsen’s collection

It is a good time to clean out your rain gutters before the fall rains start in earnest and you can slip in some astronomy by checking the debris for meteorites.   

We are familiar with meteors or shooting stars that leave streaks of light as they burn up in Earth’s atmosphere but 5 to 300 tons of space dust and debris hit the Earth’s surface every day. Impacts of large meteorites are rare but micrometeorites, those that are smaller than a grain of rice (50 µm to 2 mm in diameter) are quite common.  A rough estimate is that one micrometeorite lands in any square meter per year so your roof might bear a number of micrometeorites.  

The challenge is separating the micrometeorites from the other terrestrial debris and using a good magnet to pull out nickel and iron laden rocks is the key. An easy way to collect them is to place some strong magnets in a plastic bag and hang it near the outlet of the rain gutters. The magnet collects the nickel- and iron-laden micrometeorites, plus other magnetic debris,  as the rain washes them off the roof. The next step is to use a microscope to separate the good stuff: micrometeorites are spherical and have a glass coating formed as they heat up when passing through the Earth’s atmosphere.  

Micrometeorites and Debris Magnified
Image credit: Wayne Schmidt – The actual width of the area covered in this image is 1/8th inch

There is a good chance that some of the “micrometeorites” you’ll identify are actually formed in terrestrial processes that put particles with the appearance of micrometeorites into the air, such as volcanic eruptions or burning coal. Jon Larsen’s Project Stardust Facebook page has detailed tips on correctly identifying the micrometeorites. Hundreds of fascinating images of micrometeorites are included in his book “In Search of Stardust“.