[meteorite-list] Fwd: Ullapool, Scotland Question

[mexicodoug at aim.com]

Barb B. wrote:

"If there is ejecta from earth floating around in space, are there 
meteorites of earth origin that have been found and classified"

Hi Barb,

This is a recurring question among meteorite enthusiasts.

At the moment, the only confirmed place lots of ejecta is floating 
around is in eBay's cyberspace.  Tektites have been called "glass 
meteorites" by some, as some aerodynamic forms have clearly traveled 
through the atmosphere and likely made it into "lower" Space.

At issue is not whether a tektite can make it into space, but rather, 
whether it can actually go into orbit or better yet escape Earth's 
gravity to make it into interplanetary space where it could impact 
bodies including and additional to the Earth.

This seems plausible.  You just have to keep in mind that to obtain 
escape velocity, you need a heck of an impact - perhaps of the 
Chicxulub type. Indeed, the theory goes that CFhixulub eject is found 
around the Earth in sediments.  Whether this is due to atmospheric 
winds or something fancier that happened in orbit after the impact, is 
an open research question.  The eject must go through the atmosphere, 
densest part first if you want Earth material to be ejected.  Most 
meteors and bolides go dark after passing through only 1% of the 
atmospheric mass from above.  That is on the order of the density on 
Mars which give us a reasonable feel of why Martian meteorites can 
happen ... so we are nor surprised that we find those.  The problem 
isn't whether eject can be sent skyward - it is how much energy in what 
sort of material could survive the reverse trip up.

In the case of an Earth meteorite, speaking here of one that was 
floating around in space, some pretty neat reverse Peru cratering 
events would have to happen.  The jury is still out on that one.  All 
tektites that I am aware of are in defined strewn fields, though the 
Australasian is the most difficult to nail down.  This would seem to 
indicate they are just splashes (like the crater Tycho on the Moon).  
Like a bouncing ball on an arc rather than something that attains orbit 
and later falls in a distinct event.  The USA strewn fields in Georgia 
and Texas are a nice demonstration.

Also, while our speculation that it ought to be possible to trick the 
atmosphere and escape Earth seems reasonable, just recognizing a recent 
earth meteorite would be difficult unless it were fresh and fusion 
crusted, or an unexplainable piece of glass found somewhere.

Anyway, no one has a smoking gun yet - the jury continues to be 
out...and up to now, I am not aware of the meteoritical Society 
recognizing tektites as meteorites to be classified in the bulletin.  
As such there is no meteorite classification for Earth, though about 
100 mostly unknown bodies are recognized - and none are a match for 
Earth.

That's my take on it, anyway.

Best wishes and Great Health,
Doug


-----Original Message-----
From: Thomas Webb <webbth1 at yahoo.com>
To: meteorite-list at meteoritecentral.com; bakers5acres at frontiernet.net
Sent: Thu, 27 Mar 2008 10:39 am
Subject: [meteorite-list] Fwd: Ullapool, Scotland Question



List,
Would someone with expertise or knowledge in the area
of earth ejecta meteorites address this question from
Barb Baker?
Thanks,
Thomas



--- Jake Baker <bakers5acres at frontiernet.net> wrote:

> From: "Jake Baker" <bakers5acres at frontiernet.net>
> To: "Thomas Webb" <webbth1 at yahoo.com>
> Subject: Ullapool, Scotland Question
> Date: Thu, 27 Mar 2008 06:54:02 -0700
>
> Thomas,
>
>
>
> After reading the Ullapool story a question came to
> mind. If there is ejecta
> from earth floating around in space, are there
> meteorites of earth origin
> that have been found and classified? Are we missing
> something here? How
> about earth origin meteorites hitting other planets?
>
>
>
>
> For some reason I am not able to send questions back
> to the meteorite list.
> This might bring up a good discussion among the
> members.
>
>
>
>
>
> Thanks
>
>
>
> Barb Baker
>
> Show Low, Arizona
>
> (45 minutes south of Holbrook)
>
>



       
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