[meteorite-list] Portales Valley and PF SF's
From: MexicoDoug_at_aol.com <MexicoDoug_at_meteoritecentral.com>
Date: Thu Apr 22 10:18:02 2004 Message-ID: <d.1ec42300.2d1538f1_at_aol.com> --part1_d.1ec42300.2d1538f1_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit I'd guess that a particular "tailwind" is not required to make the situation you describe happen, as it impacts me as a bit too simple. The particles are not falling at the same rate (terminal velocity depends on mass, cross sectional area, their ratio and aerodynamics in general, so differing "headwind" (or angled wind, etc) velocities eaisly can be an alternate explanation, as different strata of the atmosphere with different and ever changing conditions, especially for steeper angles of incidence. There are way too many meters of height to be imagining that the wind you feel sitting in a lawn chair is a uniform column extending out to space, or even of uniform density. Try flying a kite. The wind is in your face, but the kite crashes opposite what you expect, happened to me the other day at 250 feet or so. And as fart as strong tail winds in the upper atmosphere...well, in the upper atmosphere where the air is thin enough, a hurricane speed wind might not really do much at all. Most of the action is probably below 10 miles, or even less. Either way, resident time is probaby at least, if not more important than windspeeds. And on the average, the smaller particle the longer its up there. Heck, there are updrafts and down drafts, too. So maybe lighter particles were cycled a bit for good measure, increasing their resident flying time. Lots of possibilities, including that you might only be looking at 10% of the mass, the rest having vaporized, distribution, etc. worse maybe after altering course upon initial disintegration. Idle musings... Regarding terminology good point, convention for descriptors is probably a good idea, with words such as scattered, fragmented, disintegration pattern, etc. Saludos, Doug En un mensaje con fecha 12/19/2003 10:35:41 PM Mexico Standard Time, chaositymeteoritics_at_yahoo.com escribe: > My instinct is to suggest that there was a moderate to strong tailwind in > the upper atmosphere that pushed the lighter material "past" the heavier > pieces so as to make it seem to have fallen in reverse pattern. --part1_d.1ec42300.2d1538f1_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable <HTML><FONT FACE=3Darial,helvetica><HTML><FONT SIZE=3D2 PTSIZE=3D10 FAMILY= =3D"SANSSERIF" FACE=3D"Arial" LANG=3D"0">I'd guess that a particular "tailwi= nd" is not required to make the situation you describe happen, as it impacts= me as a bit too simple. The particles are not falling at the same rat= e (terminal velocity depends on mass, cross sectional area, their ratio and=20= aerodynamics in general, so differing "headwind" (or angled wind, etc) veloc= ities eaisly can be an alternate explanation, as different strata of the atm= osphere with different and ever changing conditions, especially for steeper=20= angles of incidence. There are way too many meters of height to be ima= gining that the wind you feel sitting in a lawn chair is a uniform column ex= tending out to space, or even of uniform density. Try flying a kite.&n= bsp; The wind is in your face, but the kite crashes opposite what you expect= , happened to me the other day at 250 feet or so. <BR> <BR> And as fart as strong tail winds in the upper atmosphere...well, in the uppe= r atmosphere where the air is thin enough, a hurricane speed wind might not=20= really do much at all.<BR> <BR> Most of the action is probably below 10 miles, or even less. Either wa= y, resident time is probaby at least, if not more important than windspeeds.= And on the average, the smaller particle the longer its up there.&nbs= p; Heck, there are updrafts and down drafts, too. So maybe lighter par= ticles were cycled a bit for good measure, increasing their resident flying=20= time. Lots of possibilities, including that you might only be looking=20= at 10% of the mass, the rest having vaporized, distribution, etc. worse mayb= e after altering course upon initial disintegration. Idle musing= s... Regarding terminology good point, convention for descriptors is p= robably a good idea, with words such as scattered, fragmented, disintegratio= n pattern, etc. Saludos, Doug<BR> <BR> En un mensaje con fecha 12/19/2003 10:35:41 PM Mexico Standard Time,=20= chaositymeteoritics_at_yahoo.com escribe:<BR> <BR> <BLOCKQUOTE TYPE=3DCITE style=3D"BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT= : 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">My instinct is to suggest that=20= there was a moderate to strong tailwind in the upper atmosphere that pushed=20= the lighter material "past" the heavier pieces so as to make it seem to have= fallen in reverse pattern. </BLOCKQUOTE><BR> <BR> </FONT></HTML> --part1_d.1ec42300.2d1538f1_boundary-- Received on Sat 20 Dec 2003 12:32:33 AM PST |
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