I concur. Anything must have been vaporized down to dust. Michael Farmer Sent from my iPhone
On May 6, 2013, at 8:57 AM, MEM <[email protected]> wrote: > > > IIRC a researcher( name not remembered) went to the Tunguska "strewn forest" > and took the azimuth of several thousand knocked over trees and worked up a > trajectory, altitude, and yield for the Tunguska object with matched computer > modeling. (Someone should find the research paper and correct my memory) > > The heat blast scorched trees several miles from the disruption--like the > wooden fence posts and window sills of buildings near the Trinity shot. To > release that much infrared energy the object had to be traveling at cometary > velocities (vs asteroid velocities--another major clue pointing to a comet). > It also supports the idea that nothing other than silicate vapor survived > what was equivalent to a high KT yield-- greater(?) than any "fussion bomb" > ever exploded. > > So I respectfully disagree that there are any Tunguskan meteorites and never > were. > > Elton > > > >> ________________________________ >> From: Rob Matson <[email protected]> >> To: 'Steve Arnold' <[email protected]>; [email protected] >> Sent: Sunday, May 5, 2013 11:25 PM >> Subject: Re: [meteorite-list] Million's of Dollars of Tunguska Meteorites >> may be located, just like Chelyabinsk's Meteorites: OUTSIDE of, NOT INSIDE, >> the Blast Zone. >> >> >> Hi Steve, >> >>> Robert Beauford and I were talking about Chelyabinsk shortly after the >>> fall and he asked how many Chelyabinsk meteorites were being found >>> in the city of Chelyabinsk, where all the windows had been blasted out? >>> I told him that, as I understood it, the strewnfield was farther "down >>> stream" because inertia carried the rocks further beyond the blast, >>> like what almost always happens with fireballs. >> >> The real reason nothing will be found in the city of Chelyabinsk itself >> is that the meteoroid did not pass over the city. The closest point to >> Chelyabinsk under the fireball path was 35 km to the south-southeast. >> Even Korkino was north of the fireball's path. The main burst was >> about 26 km above the city of Pervomayskiy, but prevailing winds >> were to the southeast, so the closest meteorites would have fallen >> south of that city. >> >>> We later talked about how the Tunguska event of June 30, 1908, >>> was bigger than Chelyabinsk it seemed, but probably not as big as >>> the 101 crater forming event of Sikhote Alin, Russia of Feb. 12, >>> 1947. Certainly, Tunguska was not as big as what caused the >>> near-mile-wide Barringer Crater in Arizona. All of a sudden, it >>> hit Robert..."Maybe there really should be Tunguska meteorites, >>> but not where everyone has been looking for the last 105 years!" >>> ... So why would there be Tunguska meteorites amongst the >>> fallen trees at the Tunguska blast zone? >> >> I agree that if meteorites made it to the ground, you would not >> expect them to be concentrated at the epicenter of the terminal >> burst (presumably the center of the fallen tree zone). But they >> would almost certainly be within it. The Tunguska terminal burst >> was at rather low altitude (likely 10 km or lower), while the >> radius of the zone of devastation is something like 25 km. So >> unless Tunguska's entry angle was very shallow and/or upper >> atmospheric winds were extremely high, it would be difficult >> for meteorites to travel 25 km downrange of that terminal >> burst. >> >> I do not believe the entry angle for Tunguska was particularly >> steep or shallow; I think I remember the consensus is that it was >> average, e.g. 30 degrees from horizontal. [Side note: 30 degrees >> *is* the exact average entry angle, not 45 degrees.] So even if >> the terminal burst was as high as 10 km, and there was no >> atmospheric drag, meteorites could only travel about 17 km >> downrange from the terminal burst. >> >> Where meteorites would end up relative to the epicenter of >> devastation depends on a combination of the original flight >> direction, and the prevailing winds at the time and location of >> the fall. There isn't consensus on that flight direction, though >> based on the evidence I've seen I would estimate that it was >> to the west-northwest. Unfortunately, the prevailing winds >> are unknown, but you could probably bound them by examining >> several years of historical data for mid-June to mid-July for >> that general region of Siberia at around 0h UT. In fact, I think >> that would be an excellent research project! I might even >> tackle it myself... >> >>> If we are right, WHERE should someone be looking to actually >>> find the potentially millions of dollars of meteorites that have >>> been waiting to be found all this time? >> >> Based on my arguments above, *inside* the tree devastation >> zone (which isn't very helpful, given that it covers some >> 2000 square kilometers!) Flight direction favors the western >> half of that zone [hey, down to 1000 sq. km ;-) ] I would want >> to run some Monte Carlo cases with different assumptions >> for wind, terminal burst altitude and flight direction to better >> constrain the fall zone. Ultimately, the choice of wind speed >> and direction is going to drive the answer to your question. >> >> --Rob >> >> >> ______________________________________________ >> >> Visit the Archives at http://www.meteorite-list-archives.com >> Meteorite-list mailing list >> [email protected] >> http://six.pairlist.net/mailman/listinfo/meteorite-list > ______________________________________________ > > Visit the Archives at http://www.meteorite-list-archives.com > Meteorite-list mailing list > [email protected] > http://six.pairlist.net/mailman/listinfo/meteorite-list ______________________________________________ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list [email protected] http://six.pairlist.net/mailman/listinfo/meteorite-list
