[meteorite-list] Re: Tektites III (Short)

From: meteorites_at_space.com <meteorites_at_meteoritecentral.com>
Date: Thu Apr 22 09:43:32 2004
Message-ID: <20010717194758.4686.cpmta_at_c000.snv.cp.net>

First off, Kelly. You have taken things out of context from the long post which has not even been posted yet. I will be posting an abreviated version tonight, if Art does not post the original before then. Your remarks below, I will address in great detail, tonight as well, putting the remarks that you attribute to me in their proper context. I hold two jobs and my time is very limited. But you and list members will get the proper response tonight. BTW-- I don't get mad when I know that I am right... and if I be wrong I will admit it openly without anger.... Regards, Steve Schoner. On Mon, 16 July 2001, Kelly Webb wrote:

>
> Hi, Steve and All,
>
> This really will be short.
>
> a) K. P. Florensky (1963) and I. T. Zotkin and M. A. Tsikulin (1966)
> reconstructed the airburst height of the Tunguska object as 5000 meters,
> or about 3 miles. I can't give the titles; they're in Russian. Terminal
> velocity at which cascade fragmentation and airburst occurred: about
> 3350 meters/second. Dynamic pressure: about 200 kilograms per square
> centimenter. If the whatever it was had been just a little heavier
> (denser or fatter) or could have taken a little more dynamic pressure,
> there would been one helluva hole in Siberia.
> The Russians seem to be very lucky this last century. Shikote-Alin
> broke up at the last minute, too.
>
> b) "Comet Linear C/2000 A2... broke up under the influence of solar
> wind pressure, and as it heated up. Comet Kehotek (sp) did the same."
> The suggestion that solar wind pressure broke up these comets is unique
> to you as far as I can tell. The heating of volatiles and the resultant
> gaseous evisceration of the nucleus is the excepted explanation for the
> breakup of comets rounding the Sun. Solar wind may possibly be a cause,
> but you are introducing a new hypothesis.
>
> c) "I DID NOT say that they are anywhere as insubstantial as you are
> claiming. You have created a "straw man" and are running with it."
> Steve misses the point entirely when he acuses me of creating a
> "straw man." My point is that airbursts are only possible when an
> impactor cannot penetrate the atmosphere to the surface of the Earth. He
> specified a 10 km impactor that airburst, a situation that could only
> happen if the impactor had a density less than the atmosphere itself, an
> impossibility in a real universe. Above a certain mass, ground impact
> must occur.
> The point is that they would have to be that low in density to be
> that size and still airburst. The type of this argument is the "reducio
> ad absurdum" (lousy spelling) and it means if you take all his claims
> together and they imply an absurd result.
> The "math" (really arithmetic) is simple, straightforward, 8th
> grade. Now, he says, "solid ice with probably trace or measurable
> quantities of dust scattered within," which would imply a density of 0.2
> to 1.2 gm/cm^2, or back to a conventional and real-world object which
> would penetrate the atmosphere and reach the surface (fail to airburst)
> at any size over 160-200 meters or so.
>
> d) "Your step-by-step density reduction argument is faulty. It has
> assumptions that do not take into account the obvious physical nature of
> comets. Nor do they take into consideration the fact an object such as
> a comet moving at hypersonic velocity will respond in the same way than
> a much more solid body such as an asteroid will respond given the same
> speed and angle of attack."
> You get so mad, Steve, that you get it turned around. My point was
> just that, that they would behave like any object of similar mass and
> velocity. I said that over and over again.
> Then, a few pages further on, I say that: "In a sufficiently
> energetic event, nothing matters but the raw parameters of energy,"
> meaning mass and velocity, and Steve hollers, "WRONG!"
> Which is it, Steve?
>
>
> e) See RAHE, VANYSEK, & WEISSMAN, "Properties of Comet Nuclei," in
> HAZARDS DUE TO COMETS AND ASTEROIDS, pp. 597-635 on densities,
> structural strength, tidal disruption, and fragmentation of comet
> impactors. This one selection happens to discuss most of the issues
> about comets you have raised. The minimum strength of the comet body can
> be estimated from their rotation periods (too weak and they fly apart).
> They discuss the fragmentation of comets, which they attribute to
> heating, and which only occurs in 1% of short period comets and 4% of
> long period comets. The discuss how far apart the fragments of a comet
> that breaks up on the way down can fall from each other (the craters are
> so close that they overlap or are inside each other).
>
> f) True, trinitite was not formed in the exact conditions of
> tektites, but the sand at and around the base of the blast tower was in
> physical contact with a little patch of the universe whose thermometer
> suddenly read 30,000,000 degrees that July dawn! If that won't create a
> tektite, just how energetic do we have to get? (The glasses from 15
> megaton boosted fission bombs don't look like tektites either.)
>
> g) Far easier to build pyramids that make tektites.
>
> h) "Just because a cosmic body has such and such a mass DOES NOT
> mean that when it hits our atmosphere it will also hit the ground."
> I really hate to disappoint you, Steve, but that's exactly what it
> means. Above a certain mass, it's inevitable.
> But look, you are not going to take my word for it; I can tell that.
> Why don't you just take the question to someone whose knowledge you
> trust and ask them?
>
> Sterling K. Webb
>
>
>
>
>
>
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>
>
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Received on Tue 17 Jul 2001 03:47:58 PM PDT