[meteorite-list] Park Forest Strewn Field

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From: Mark Jackson <b0rtz2003_at_meteoritecentral.com>
Date: Thu Apr 22 10:21:08 2004
Message-ID: <20030725185903.6106.qmail_at_web60001.mail.yahoo.com>

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Sonny & List,

So far as I know Sonny, we are struggling to come to terms with this type of strewn field for the first time by hashing it out amongst ourselves. Sterling K. Webb was very close to the mark by pointing to the “pre-airburst breakup companions” but he couldn’t find reason for the extreme NW to SE elongation of the pattern (very good work Sterling!). Some have suggested winds aloft; that is not ruled out at all and should be characterized. I struggle mightily, however, with winds being more than a small factor in the fall pattern of PF. I believe the shockwave has very much more to do with the flattening and elongation of the perpendicular “pre-airburst breakup companion” strewn field; the reason for this is those companions fly right into the shockwave close to it’s peak pressure (right after detonation), and that must affect their flight paths to a large degree.

If it turns out to be accepted, we should call falls like PF “airburst fall fields” because it can only happen when there are companions following into an airburst shockwave. Well, before we do that, there have been a couple of other strewn fields that match the 90 degree out pattern as pointed out by Ron Baalke and others; I have not read the scientific papers associated with those falls to see what the investigators concluded, so we may be repeating work already done.

To answer some of your other questions, I have no way of telling you what any particular strewn field will look like; they are such dynamic events it would be impossible. There are some basic tenets of physics that will apply however. If you take a line called the velocity vector of the original body and intersect it with the earth, that’s what DoD calls the “straight-line intersection”. In a vacuum, undisturbed by any other forces, the impact point would be right on that point. In a total breakup situation, like Columbia, the heaviest pieces will always be closest to the straight line intersection (the far end of the strewn field). Better put, heaviest objects will always be closest to the velocity vector AND the straight-line intersection because they carry the most kinetic energy and are therefore the hardest objects for outside forces to move off course.

Something else to remember: these are all pre-impact elements we are discussing here; this is WAY different than discussing a post-impact ejecta pattern.

I have found what I suspect to be meteorite fragments at my crater-possible site. Nothing I have found has yet been confirmed to be of impact or meteoritic origin, however. I am not a PhD or anything I just do this stuff because I like it and I have great interest in it.

Finally I don’t know what a “meteorite recovery team” is . . . but I want to sign up!

Kindest Regards,

Mark

---------------------------------
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<DIV>
Sonny & List,<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>
 <o:p></o:p>
So far as I know Sonny, we are struggling to come to terms with this type of strewn field for the first time by hashing it out amongst ourselves. Sterling K. Webb was very close to the mark by pointing to the “pre-airburst breakup companions” but he couldn’t find reason for the extreme NW to SE elongation of the pattern (very good work Sterling!). Some have suggested winds aloft; that is not ruled out at all and should be characterized. I struggle mightily, however, with winds being more than a small factor in the fall pattern of PF. I believe the shockwave has very much more to do with the flattening and elongation of the perpendicular “pre-airburst breakup companion” strewn field; the reason for this is those companions fly right into the shockwave close to it’s peak pressure (right after detonation), and that must affect their flight paths to a large degree.<o:p></o:p>
 <o:p></o:p>
If it turns out to be accepted, we should call falls like PF “airburst fall fields” because it can only happen when there are companions following into an airburst shockwave. Well, before we do that, there have been a couple of other strewn fields that match the 90 degree out pattern as pointed out by Ron Baalke and others; I have not read the scientific papers associated with those falls to see what the investigators concluded, so we may be repeating work already done.<o:p></o:p>
 <o:p></o:p>
To answer some of your other questions, I have no way of telling you what any particular strewn field will look like; they are such dynamic events it would be impossible. There are some basic tenets of physics that will apply however. If you take a line called the velocity vector of the original body and intersect it with the earth, that’s what DoD calls the “straight-line intersection”. In a vacuum, undisturbed by any other forces, the impact point would be right on that point. In a total breakup situation, like Columbia, the heaviest pieces will always be closest to the straight line intersection (the far end of the strewn field). Better put, heaviest objects will always be closest to the velocity vector AND the straight-line intersection because they carry the most kinetic energy and are therefore the hardest objects for outside forces to move off course. <o:p></o:p>
 <o:p></o:p>
Something else to remember: these are all pre-impact elements we are discussing here; this is WAY different than discussing a post-impact ejecta pattern.<o:p></o:p>
 <o:p></o:p>
I have found what I suspect to be meteorite fragments at my crater-possible site. Nothing I have found has yet been confirmed to be of impact or meteoritic origin, however. I am not a PhD or anything I just do this stuff because I like it and I have great interest in it.<o:p></o:p>
 <o:p></o:p>
Finally I don’t know what a “meteorite recovery team” is . . . but I want to sign up!<o:p></o:p>
 <o:p></o:p>
Kindest Regards,<o:p></o:p>
 <o:p></o:p>Mark</DIV><hr SIZE=1>
Do you Yahoo!? 
Free <a href="http://us.rd.yahoo.com/mail_us/tag/*http://calendar.yahoo.com">online calendar</a> with sync to Outlook(TM).
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Received on Fri 25 Jul 2003 02:59:03 PM PDT

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