meteorite authentication

[Lester]

Hi all, some of my farm machinery has magnets inside the wheel so that a speed sensor can acuratelly measure the ground speed. On these magnets acumulates soil and small stone particles. I have removed these and taken a photo of the largest of them. Does anyone know where I can send these to find out if they are terrestrial or meteorite?

These have built up over a few years when boomspraying my 1600 acre farm many times.

[Matt Wastell]

Hi Lester - this could be interesting!
I have just gotten into meteorites (I just purchased some) - these site may help?
http://en.wikipedia.org/wiki/Meteorite
ttp://www.meteoriticalsociety.org/simple_template.cfm?code=home_intro&CFID=11828443&CFTOKEN=35590306

A couple of thing I remember -
A lot ate found on farms!
Most meteorite are magnetic
They could / should have blackening and some kind of melt

Good luck and let us know how you go!!!!

[Blue Skies]

Also have a look at these pages of Meteorwrongs (http://meteorites.wustl.edu/meteorwrongs/meteorwrongs.htm) for comparison.
hmm, these pages look helpful (http://www.meteorite.com/Meteorite_Identification.htm), too.

[Lester]

Hi Matt and Jacquie, thanks for your replies. I would like to find somewhere within Australia to get these authenticated. I have also read that if meteorites are found in S.A. and W.A. they remain the property of the state government, the other states the finder can own them. Well that dampens my enthusiasm for looking for meteorites that some @###$$ nice department can claim as theirs from outerspace. I may try a phone call to the Adelaide Museum and see what I can find out.

[sjastro]

An analytical laboratory can test the the samples for Nickel using X-ray spectroscopy.
The presence of Nickel is a sure sign the sample is a meteorite.

Telling the laboratory what to look for and how to test it will also reduce costs.

Regards

Steven

[CraigS]

Ok .. I'll be the donkey … why is the presence of Nickel a 'sure sign' it is a meteorite ?
:)
Cheers

[jjjnettie]

Here you go Lester.
http://www.meteorites.com.au/found.html

[sjastro]

Craig,

Nickel content in iron meteorites varies from about 5 to over 20%. This differentiates from man made iron objects where the nickel content is zero. Naturally occurring iron as an element is very rare as are Iron Nickel deposits.

A test for Nickel is the most conclusive test available for Iron and stony iron meteorite identification.

The fact that Lester is also picking up soil on the magnets is not a good sign. If Neodymium magnets are being used these can pick up hematite, which suggests the small stones may be basaltic in origin.
A specific gravity test would help here, but a test for Nickel is the way to go.

Regards

Steven

[Lester]

Thanks jjj, that is what I was looking for. I have emailed Jeff, with the photo.

[Lester]

Thanks for your input Steven. Yes very likely they are not meteorites. But I just want to test it.

[CraigS]

Thanks Steven .. interesting ..

I've just been doing some more reading on this. Wiki mentions that by applying a chemical test on the proportions of Ga, Ge and Ir, they can further classify iron meteorites into classes corresponding to distinct asteroid parent bodies! Eg: the best candidate for a Class IIE iron meteorite is 6 Hebe !

.. Interesting stuff !

Good luck Lester .. I'll be interested to see what comes of it .. let us know!

Cheers

[Suzy]

Hi Steven,
Can I please ask a question?
Recently I watched a documentary and the guy on it said that if you put an empty bucket with a magnet in it under a down pipe, when it rains, the rain will wash down the meteorite bits into the bucket which the magnet will attract. He didn't mention anything about getting authenticity on them. I was going to try this. Will they be meteorites or would I still have to prove authenticity? Thanks.

[sjastro]

Hi Suzy,

The advantage for looking for micrometeorites washed out of your down pipe is that it will be far less contaminated with material that can be mistaken for micrometeorites.

So it's highly probable that the magnetic particles washed out of your down pipe are micrometeorites. To be 100% certain however it would need to be checked for Nickel.

Regards

Steven

[sjastro]

Here is an example of a meteorwrong.

The rock has a "fusion crust" and is highly magnetic.

The X-ray spectrometer reveals it is nothing more than a piece of basalt.:(
Apart from the lack of Nickel, the real killer is the presence of Silicon in the form of silicates (the Si Ka peak) which is terrestial in origin.

Regards

Steven

[CraigS]

Hmm ..

We might have to take bets on that one .. give it a go, Suzy.

I guess it depends on what materials your roof is made from. I have a lot of gal steel used in my roof; my guttering and downpipes are made from the same material. If there was micrometeorite material in the runoff, it would be heavily polluted with contaminants, so I guess I'd be looking for the proverbial needle-in-the haystack …

Separating the real stuff from the pollutant would be the main issue .. (ie: deciding what to send to the labs would be the main issue …??...)

Cheers

[sjastro]

That's were a magnet comes into good use Craig.
If you were getting galavanized material plus bare metal in the contamination, I think a new roof would be in order.:)

Regards

Steven

[CraigS]

Well I know finding micrometeorites might be fun, but I didn't know it would result in my having to replace my entire roof !! :)

I mean, I know astrophotography is an expensive past-time (for example), but looking for rocks seems to go way beyond that !! :)
:lol: :)

This is no longer just an interesting past-time …. this is serious !!!

Good luck Suzy !!
:)
Cheers

[CraigS]

As an example, if I was to go and stick a magnet into the dirt outside my house, I'd end up with the magnet being heavily covered in what would probably amount to 'iron filings' (after analysis). I have no idea what the source really is .. but the evidence exists.

How can I pick out the samples (for analysis) from all of that? :question:

We need a home-style nickel detector !
:)
Cheers

[Suzy]

That's why it's better to collect them off your roof via the down pipe- less contaminants. :D

Steven, thanks so much for all your help. :)

I'm going to buy myself a bug u shaped magnet :D.
Craig you should join me in this experiment Now, I'll be hoping for rain - just plain wrong isn't it? :screwy: :lol:

[astroron]

Craig and Suzy,if I drag a magnet across my Paddock it gets lots of browny metal bits on it ,I no need to dig into the ground.
Where do the bits come from except maybe above :shrug:

[jjjnettie]

Here's some I collected last year. http://www.iceinspace.com.au/forum/showthread.php?t=61604&highlight=micro+meteorites

[jjjnettie]

from Wiki
Micrometeorites
In 1946, during the Giacobinid meteor shower, Helmut Landsberg collected several small magnetic particles that apparently were associated with the shower.[2] Fred Whipple was intrigued by this and wrote a paper that demonstrated that particles of this size were too small to maintain their velocity when they encountered the upper atmosphere. Instead, they would quickly decelerate and then fall to Earth unmelted. In order to classify these sorts of objects, he coined the term "micro-meteorites".[3]
This early work, in collaboration with Fletcher Watson, led the Harvard Observatory to build a station observatory to directly measure the velocity of the meteors that could be seen. At the time some argued that meteors were extra-solar in origin, while others claimed they were leftovers from the formation of the solar system. These direct measurements were able to locate the source of the meteors, demonstrating that the bulk of material was leftover from comet tails, and that none of it could be demonstrated to have an extra-solar origin.[4] Today it is understood that meteors of all sorts are leftover material from the formation of the solar system, part of the interplanetary dust cloud or the various other objects made up from this material, like comets.[5]
These studies were based on optical measures only. In 1957 Hans Pettersson conducted one of the first direct measurements of the fall of space dust on the Earth, estimating it to be 14,300,000 tons per year.[6] If this were true, then the meteor flux in space was much higher than what the telescopes were seeing. If true, meteors would present a very serious risk to missions deeper in space, specifically the high-orbiting Apollo capsules. To determine which measure was more accurate, a number of additional studies followed, including the Pegasus satellite program. These showed that the flux in line with the optical measures, around 10,000 to 20,000 tons per year.[7]

That's a hell of a lot of debris falling from the sky each day. :eyepop:

[AstralTraveller]

If Steve is right and Neodymium magnets can pick up hematite then I'll punt for bits of broken up laterite. It's widespread in Oz and given the age of the soils on the EP there's bound to be plenty there. Add a bit of farm machinery to break it up and Bob's your uncle.

Have you looked at them under a magnifying glass? Laterite can develop a good approximation of a 'fusion crust' but you should be able to see entrapped quartz grains somewhere. Laterites also tend to be mottled but I imagine that will be difficult to see on such small fragments. Another easy test would be to measure the density. You probably have all the equipment lying around (something to weigh one and something to measure the volume of water displaced). You'll need to check but I believe the density of metalic/stoney of meteorites would be quite high (sg > 4 perhaps) whereas I'd guess that laterite is about 2.5.

The "home-style nickel detector" is a hand-held X-ray fluorescence spectrometer (XRF). eg http://www.bruker-axs.com/handheldproducts.html?utm_id=17&utm_term=XRF%20analysis
http://discover.asdi.com/new-handheld2---portable-and-precise---ppc/?utm_campaign=RS---PPC---Field%2FGround-Truth-ad-groups&utm_source=PPC%20&gclid=CIncq5DduKcCFQbbbgodFlmZ_A
They seem to be the bees knees for portable non-destructive analysis. At work the archaeologists are keen on one to do things like analysis of the 'paint' used in cave paintings. They would need to top-of-the range model and I think I heard $50k mentioned. So you could probably pick up a basic metal-assay model for the cost of one or two SDMs :D.

[sjastro]

I'd use a microscope. I suspect micrometeorites are more rounded in shape, iron filings would have sharper edges.

Larger pieces such as slag are identified by a lack of fusion crust.

Regards

Steven

[CraigS]

Ok JJJ, Astroron and Suzy;

I'm not saying that micrometeorites don't exist ! After all, the entire Earth was some kind of meteor, at some stage !!
All I'm saying is that rooftops gather a lot of other contaminants, which would require separation by some, (several) means, before sending it off to a lab.

Depending on your location (remember there are lots of us who live in cities), you'd have to consider the history of the collection site.

David: Cool instrument .. that, and a microscope is what I'm talkin' about !

Cheers
PS: Does anyone know what the lab analysis costs ? :shrug:

[AstralTraveller]

The surface area of the Earth is 510,072,000 km2. If we assume 20,000 tonnes of meteorites p.a. distributed evenly then the rate of fall is 0.00003921 tonnes per km2 per year or 0.00003921g/m2 per year. I regularly weigh out 40 micro-gram samples of calcium carbonate and that is about 6 specks on the end of the micro-spatula. Given that meteorites are denser than calcium carbonate you are down to about 3-4 specs. Alternatively that is one milligram size particle every 100m2 per year. Of course micrometeorites have been raining down for a very long time but they also would weather away in the soil so I expect the density would remain very low. Micrometeorites are out there and we can all collect them but don't expect to trip over one; and not every interesting-looking spec has to be a micrometeorite.

[jjjnettie]

That's so true.
The ones I found were sorted out of many dozens of samples from my sieve.
I used macro photography to examine them closer.
There is a great book on the subject, "A Field Guide to Meteors and Meteorites" by O. Richard Norton and Lawrence A Chitwood.
I highly recommend it.
http://www.springer.com/astronomy/astronomy,+observations+and+techniq ues/book/978-1-84800-156-5

[AstralTraveller]

Thanks for pointing out that book. It looks good and I've just ordered a copy. :thumbsup:

[Lester]

I did not get a reply to my email, so I guess that means they are just Earthly rocks. Some reply would have been good. Hope others have more luck.