(meteorobs) Meteorite pix

stange stange34 at sbcglobal.net
Fri Dec 5 11:01:07 EST 2008


I was wondering if that collision could have ejected debris away from 
Jupiter. But you have settled that question rather thoroughly.

It would appear my internal Geiger-Muller Victorene 1B85 tube contained no 
quenching gas and has self destructed with a run-away avalanche of secondary 
emission. I must now frame Sodium Iodide Crystals from Scintillators into 
eyeglasses that I may see radiation more clearly.

All in good fun. :-)
Thanks, Larry


----- Original Message ----- 
From: <mexicodoug at aim.com>
To: <meteorobs at meteorobs.org>
Sent: 2008/12/05 01:28
Subject: Re: (meteorobs) Meteorite pix


> "Perhaps the excitement over the piece under examination is the chance
> it
> might be a product of the Jupiter-Asteroid collision which may have
> caused
> additional isotopes to be formed in the asteroid fragments."
>
> Hello Larry,
>
> It is very unlikely that such a scenario is being considered.  Are you
> referring to Shoemaker-Levy 9 and suggesting that after collision with
> Jupiter, it swam out of that intense gravitational field and
> atmosphere, then navigated with JPL slingshot precision to Earth 15
> years later in the form of intact rocks with a density greater than
> quartz :-)
>
> The journey from the asteroid belt (source so far of all ordinary
> chondrites for which orbits have been determined) to Earth delivery
> seems to be without exception a more than 1,000,000 year long dynamic.
> This lower limit has been been supported by the previously described
> cosmic ray exposure ages as well as CR fission tract densities.
>
> A more likely explanation is that whoever related the story of
> "unusually high radioactivity", didn't accurately follow that it simply
> was a pristine specimen and typical meteorite - a good candidate for
> doing cosmic ray exposure testing via isotope concentrations and ratios
> to try to ferret out this info, to gather whatever information shakes
> out.  Or maybe the Saskatchewan cold was affecting the performance of
> an unwitting geiger counter that had been rusty in storage a while that
> someone stuck by the rock in the field.
>
> Or maybe it was a general statement that anythings in space have a
> trace amount of systemmatic radioactivity dependent on their history
> and not present on Earth due to magnetic and atmospheric shielding of
> CRs. Meteoroids in situ present greater dangers to astronauts visiting
> them when the cosmic rays hit the astronauts directly due to no
> magnetic protection or atmosphere around the meteoroid, as well as the
> worse ejected immediate byproducts from the surface for any asteroid
> miners.  It is this active cosmic ray particle bombardment and
> byproduct dangers in space that is hard for many of the public to
> separate from the supposed "radioactivity" of space material, i.e.,
> meteorites, in the popular press.  Once on Earth, the light bulb gets
> turned off- well in this case the cosmic particle bulb and it is a
> passive process pesists for a very tiny concentration of isotopes.
>
> As Chris also mentioned, this is a trace amount.  Any claims anywhere
> near approaching a dangerous threshhold would raise quite a few
> scoffing eyebrows among meteoriticists... It has a whole lot less than
> the radon accumulating basements many list members live on top
> of...anyway this is my understanding FWIW, which you already seem to
> have acknowledged ... still, it might make a good plot for a Canadian
> horror flick explaining that Canadians' teeth will fall out whether
> they look for "highly radioactive" Unwin meteorites or go back to
> playing hockey.  Can't win :)
>
> Best wishes, Great Health,
> Doug
>
>
>
>
>
>
>
> -----Original Message-----
> From: stange <stange34 at sbcglobal.net>
> To: Global Meteor Observing Forum <meteorobs at meteorobs.org>
> Sent: Fri, 5 Dec 2008 12:22 am
> Subject: Re: (meteorobs) Meteorite pix
>
>
>
> Acknowledged Chris.
>
> Perhaps the excitement over the piece under examination is the chance
> it
> might be a product of the Jupiter-Asteroid collision which may have
> caused
> additional isotopes to be formed in the asteroid fragments.
>
> Larry
>
> ----- Original Message -----
> From: "Chris Peterson" <clp at alumni.caltech.edu>
> To: "Global Meteor Observing Forum" <meteorobs at meteorobs.org>
> Sent: 2008/12/04 10:08
> Subject: Re: (meteorobs) Meteorite pix
>
>
>> The only difference between cosmic rays in the Solar System and
> outside it
>> is that locally you have a slightly higher rate of relatively low
> energy
>> particles from the Sun. The planets have no effect at all. By most
>> standards, almost no meteorites would be considered "radioactive",
>> although
>> most natural materials, meteorites included, have some low background
>> activity. Most radioactive isotopes present when the objects formed
> have
>> long since decayed to very low levels, and regardless of location,
> the
>> rate
>> of cosmic ray impacts and occasional conversion of material to
> radioactive
>> species is far too low to result in significant radioactivity in bulk.
>>
>> Chris
>>
>> *****************************************
>> Chris L Peterson
>> Cloudbait Observatory
>> http://www.cloudbait.com
>>
>>
>> ----- Original Message -----
>> From: "stange" <stange34 at sbcglobal.net>
>> To: <meteorobs at meteorobs.org>
>> Sent: Thursday, December 04, 2008 10:52 AM
>> Subject: (meteorobs) Meteorite pix
>>
>>
>>> Is it thought that meteroids entering the solar system from a travel
>>> through
>>> the galaxy would not be radioactive from encountering primarily
> higher
>>> energy cosmic rays, but those meteoroids formed (within) the solar
> system
>>> and coming from orbits within the asteroid belt would be radioactive
> from
>>> isotope formation due to planetary magnetic focussing of lower energy
>>> cosmic
>>> rays?
>>>
>>> Is my understanding correct that rates and velocities of cosmic
> radiation
>>> that cause isotope formation, would be dramatically different in
> these
>>> two
>>> situations?
>>
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