To introduce myself, I'm Joe, and new to Cloudy Nights, but not new to our hobby. This is my first post.
I've been an observer, ATM, and photographer since the early 1960's (or before, really).
Additionally, I've had an interest in micrometeorites since about 1967. I collect them from rainwater.
Simply put, I gather about a gallon of rainwater as it falls from the sky in a wide, clean vessel held well above the ground (to avoid soil splattering in), say, on a picnic table.
Then, with the water gathered, it's time to evaporate all of the water (but for about 1/4 ounce). One can evaporate the water passively, but that's slow. Lately I have done it in a large clean stainless steel uncovered cook-pot on a low flame on the stove. It takes a few hours. You only have to pay attention when there's just a little water remaining.
When most of the water is evaporated (or all of it, if you ignored the process, and it burnt up the organic matter ("dust"; pollen; plant-parts; etc.) in the rainwater), remove the pot from the heat, and let it cool completely. Then, slosh in about an ounce of rubbing alcohol (70 percent; or, 91 percent), and scour the pot well with a perfectly clean object of some kind (a gloved finger, say), and get all the solid residue wet with the alcohol, and suspended in the alcohol. You don't have to be completely thorough.
Then, pour the ("dirty") liquid into a small clear vial, and cap it with a non-porous cap (cork is prob. not the best).
Anytime you like, SHAKE the vial to suspend the contained particles in the light liquid. The tiny particles will settle pretty fast in the thin, low-viscosity, mostly-alcohol vehicle. Then, stand the vial upright somehow, and place a MAGNET somewhere touching the vial, say, half-way up its height. Go do something else for half-an-hour.
When you come back, you'll see that the liquid has gone nicely CLEAR, and that the bottom of the vial is coated with dark brown "dirt", while the inside of the vial near the magnet is ALSO coated with "dirt". I contend that the magnetic stuff is MOSTLY of extraterrestrial origin (micrometeorites).
To prove that the magnetic stuff is micrometeorites, keep the magnet near the tube, and remove a sample of the magnetic stuff, and place it on a microscope slide, under a decent microscope. Using a couple hundred power or more, look at the particles. Many -- or MOST -- are extremely small, JAGGED, and very sharp. They are not rounded, not fused.
IF these are indeed micrometeorites, they are tiny enough to cool themselves as they enter the Earth's atmosphere. Their ratio of surface-area to volume is HUGE. Hence, THEY DO NOT MELT by friction on entry, nor are their sharp edges even blunted. They "land" intact.
There may be lots of stony-meteorite dust, too, but if it is not even slightly magnetic, well, it will not stick to the side of the vial near the magnet in contact with the vial after shaking.
Now, I have not carried out further tests of this material besides magnetic and microscopic tests. I've considered spectroscopy of vaporized samples, and x-ray fluorescence spectroscopy of the solid samples, but have not gotten around to these tests.
I'll be vastly dismayed if someone proves to me that the magnetic material collected in this way is NOT really micrometeorite material. But if someone has that verdict authoritatively, I will of course be happy to learn its origin ...after all these years, if not extraterrestrial.
Good luck to everyone who carries out the above simple procedure!
With best regards,
> Has anyone here done this sort of thing?
Edited by desert_woodworker, 30 April 2016 - 09:02 PM.