A quick smug

[kaberett]

(At some point I think I probably need to put together a post that just contains the first lines of anecdotes that make people pull the "you just said what" face when they suddenly become relevant. Like "the time I taught the daughters of an oil sheikh how to ride", or "the time I broke a hammock with an opera singer", etc etc etc.)

Anyway, the point is, I have to a few of you now mentioned The Time I Found A Meteorite Under My Desk.

It is quite a nice meteorite. It is about the age of the solar system, i.e. about 4.6 billion years. You can tell this by looking at it.

This is a photograph of my bookshelf at work, somewhat out of date, but nonetheless featuring several of the major textbooks. (I can tell I'm turning into a grown-up because I actually have my own copies of a pile of texts.) Also: a small silver circle (handlens) and a yellow perspex block containing an oddly-shaped lump of metal.


Close-up of the meteorite.

Not excellent images by any means, but what they do show is that this lump of rock has beautifully developed Widmanstätten patterns. What you can't see is the black crust around the edge of the meteorite, acquired on entering the atmosphere.

Entertainingly, this lump of four and a half billion years old rock does not, in point of fact, have any identifying information on it at all. It damn well ought to at least have a sample number on it - it probably came from a museum collection before it found its way down the back of my desk - but it doesn't.

So there we go.

Comments

[jelazakazone]

So, did you find it covered in the yellow plasticy stuff? It's AWESOME and yes, the pattern is very identifiable.

Funny story about how I, a layman, know something about these patterns on meteorites. A few years ago I told dh I wanted a ring for our 10 year anniversary. 10 yr anniversary came and went with no ring. So, I got to work and started doing research so I could have one for the 11th anniversary. One of the rings that came up during this time was meteorite rings. We actually went to some posh store and tried them on, but alas, they were sooooo boring, we decided they weren't worth it.

In the end I got a ring that is perfectly suited to me and it cost a fraction of the amount of the meteorite ring. Chris Ploof's store will give you an idea of what we were looking at.

[kaberett]

Ooooh, nice.

[catyak]

It is quite a nice meteorite. It is about the age of the solar system, i.e. about 4.6 billion years. You can tell this by looking at it.

I'm afraid when I read this I wondered if it had a date code etched onto its surface.

[kaberett]

It does. Sort of. In that the that's what the scale of the Widmanstaetten lines tell you :-)

[hairyears]

It might be a bit older than the solar system, if you count the age as starting from the formation of a recognisable accretion disk. The question is whether whether the meteorite is itself an accretion from dust, a fragment of an accreted object in the early disk, or was ejected in its present form from a stellar explosion (give or take a knock or two).

[kaberett]

Scale of the lamellae in the Widmanstaetten lines gives you a pretty good idea :-) It's an exsolution pattern - leave an iron-nickel mix long enough and it'll unmix via diffusion (they don't actually fit terribly well in one another's crystal structures) and... tada!

[hairyears]

...So it's spent some time in a large body - large enough tp cool slowly.

[dreamfracture.insanejournal.com]

Widmanstätten patterns! I know a teensy bit about those. They showed up in a Call of Cthulhu game I ran, as evidence that an antique iron urn had, in fact, been carved from part of a stupendously large meteorite.

Said urn had a Colour Out Of Space in it. The results of opening it weren't pretty.

[kaberett]

:-)

[oursin]

Nice!
I once had some bones from the Broad Street plague pit in my office. In a plastic carrier bag. This was perhaps an extreme example of Weird Shit Discovered Among Someone's Archives.

[kaberett]

*snerk* Brill.

[calissa]

You've just reminded me that I had some photos of pyrosmalite (at least I think that's what it is) to share that I need to post sometime.