[meteorite-list] FW: Rocks from Space Picture of the Day - May 8, 2010

From: Jason Utas <meteoritekid_at_meteoritecentral.com>
Date: Sat, 8 May 2010 17:26:48 -0700
Message-ID: <z2p93aaac891005081726zf0276531gb82bdb811ee09bbb_at_mail.gmail.com>

Hello All,
All we can do is look at this object...objectively.

Sterling made some good points; while it might be possible for an
"iron meteorite" to attain such a shape...it's not likely.
It seems much more likely to be a man-made object if only
because....it's a very inorganic shape. It's one thing to claim that
a given object might be a meteorite because there's nothing that
*proves* that it isn't one. And I agree - in this case, you can't
really prove that what you're looking at is or isn't man made.

But take a look at it.

We're either arguing that a piece of metal found near a set of train
tracks that looks to have been machined and hole-punched is man made,
or we're saying that said piece of metal is one of the more strangely
shaped "iron" meteorites ever found.

What's more likely?

Well, let's look at this object's characteristics. We have a thick
central ring, a thin outer rim (partial), and a nice hole *punched*
clean through the middle.

I've got no real problems with the supposed leading surface. Sterling
notes that in order of it to be a true "australite" form, it would
need to have melted through completely, and would thus have ring
waves. If we assume, for argument's sake, though, that it's simply
oriented in the fashion that most meteorites are...the only iron
meteorite that I know that ever formed true ring-waves was Boogaldi
(see Buchwald). So I wouldn't expect to see ring-waves. You can note
some fine pressure waves in the photograph of the Sikhote later on in
my message, but...keep an eye out for that when you get there.

The edges on this thing, both inside and out, are very disconcerting.
The central hole does look as though it has been *punched* out. Larry
notes other holes that have supposedly been punched out of
Sikhote-Alins. Even if they had rough edges, I would suggest that
those holes were formed by thin areas in the meteorite breaking away
due to atmospheric stresses, and the resulting edges failing to melt
over. I've seen such holes, and that is how I would explain their
formation; it seems more likely than their having formed through
mid-air collisions precisely at weak points on the irons. Craters on
Sikhotes are simply too rare to account for the formation of any
number of holes.
Think about it.
If one iron in several hundred or so has a crater on it, how often are
you going to get a crater on an iron in the 'perfect' location where
the meteorite is thin enough to get punched out? And given that most
craters are only a mm or so in diameter anyways, it hardly seems
likely that the typical crater-forming impact could break through even
a few millimeters of metal.

I've been collecting Sikhote "craters" for the past few years, and
have some pretty snazzy examples. Here's one of my favorites.

http://picasaweb.google.com/MeteoriteKid/Irons#5417269890462024562

Compare to the hole in Larry's find. The force required to punch such
a uniform hole through such a small piece of metal would have to be
simply enormous, because the specimen itself is so small. It's one
thing to punch a dent in a piece of metal that's 50g and has some
inertia of its own. It's another matter entirely to punch a hole
clean through a 0.1 gram piece of metal. Think about the mechanics of
it. To punch a hole through something so small, you'd need to have
something holding it still -- otherwise it would simply change
direction and you'd have an inelastic collision. It just doesn't seem
physically possible, in my mind.

So, that outer edge.
Half of it looks so clean-cut, it looks machined, and the other half
looks...well, as Mike notes, it looks as though it gave way to stress.
 It's not melted; it's torn. And while you're calling that thicker
rim a roll-over lip, I would like to point out that if it were such a
feature, it would be composed of melt. Even irons from frothy, melted
fusion crust.

http://www.flickr.com/photos/cameteoritefinder/2336539994/in/set-72157594532840297/

But this feature exhibits the same texture as the 'front' of
the...thing, whatever it is.

So...

What I see here is a piece of metal with a shape only vaguely similar
to that of known atmospherically ablated objects....that is most
likely a piece of man-made metal with a thin coating of oxide.

Regards,
Jason


On Sat, May 8, 2010 at 1:27 PM, Joe Kerchner
<skyrockmeteorites at yahoo.com> wrote:
> Sorry about that, I dont know why, but I thought it was found a couple
> years ago, sorry for my mistake.
> Larry had told me the story about this
> piece while out for dinner while in WI hunting. I got the impression it
> was found a few years ago. again I apologize for not reading the caption better, my bad. But still trust in Larry. Even tho nobody here seems to think it could be a meteorite. However I am not 100% convinced, but i trust in Larry's opinion on this. He has been doing this for a while now and has found many meteorites before, and I am sure even more meteorwrongs. But anyone could be wrong. I also dont see MJ posting a wrong as the RFSPOD
>
> ?Best Wishes,
> Joe Kerchner
> http://illinoismeteorites.com
> http://skyrockcafe.com
>
>
>
> ----- Original Message ----
> From: Darren Garrison <cynapse at charter.net>
> To: meteorite list <meteorite-list at meteoritecentral.com>
> Sent: Sat, May 8, 2010 4:25:22 PM
> Subject: Re: [meteorite-list] FW: Rocks from Space Picture of the Day - May 8, 2010
>
> On Sat, 8 May 2010 12:17:38 -0700 (PDT), you wrote:
>
>>if he says it is a meteorite after having it for
>>a few years and examining it in person,
>
> FWIW, the caption says that it was found in "April, 2010" (didn't say if it was
> on the 1st) so it falls short of a few years yet.
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Received on Sat 08 May 2010 08:26:48 PM PDT