My articles are all stored away, and it’s been years since I read them, but I’ll swear that the figure of megatons is too damned big. When the Hiroshima bomb exploded the Russian newspapers compared the bomb’s effect to that of the Tunguska meteorite, since they were roughly equivalent. I’m sure I’m not misremembering the article I noted above.
Look at it this way – trees were knocked down radially out to a distance of about ten miles. That’s the range of the blast effect, not the thermal effect. In a ten megaton blast the fireball alone is about that big. (I know – I live about that far from Boston, and I figure if anyone decides to nuke the city in a big way my number’s up). The blast effects from a ten megaton bomb go a lot further out.
I realize that, with this crowd, I run the risk of offending someone who was Jack (or did you call him John?) Williamson’s very best friend in the whole wide world but those books were stupefyingly dull. I kept reading them (it was either that or stare out the train window at the backs of closed factories) in the vain hope they’d get better but they never did. Turned me off to Williamson permanently.
Well, J&R cited Krinov’s Giant Meteorites as well as V. Fesenkov (Soviet Astr., 10, 195 (1966)) and A. Zolotov (Soviet. Fiz. Doklady, 12, 108 (1967)) for their 0.2-20 megaton number. And, as noted, Vasil’ev had 13 citations for the same 10^22-^24 erg figure. It’s a pretty common range, and I can’t recall having seen anything smaller in the literature. I’ll try to check the Krinov over the weekend and see how he arrived at his estimates, though.
Meanwhile, could the comparisons in the Russian newspapers have been based on features of the two blasts other than their magnitudes? For instance, the Russian on-site observers were struck by the fact that the trees in the grounds of the Agricultural Exposition Hall at ground zero in Hiroshima were still standing – it reminded them of Kulik’s “telegraph-pole forest.”
If a black hole punches through the earth and explodes…well, how can this happen? If I remember correctly, an evaporating black hole does just that because it’s leaking matter/energy faster than it’s taking it in (at least, from a distant perspective).
But, if such a thing hits the Earth, isn’t it going to absorb a lot of mass? I can sort of swallow the idea that the thing, if it was moving fast enough, might just plow right through the planet and keep going, but wouldn’t it simply bore an ever-widening tunnel through the Earth, probably absorb a mountain-or-two-sized mass along the way, and then keep going to blow up someplace else?
And as for being a biologist, well, shucks, I’m nothing but an ex-Soviet Area/Poli Sci major become systems engineer. It’s only the occasional word from “Jack Adler” keeps me more or less on the straight-and-narrow where astrophysics is concerned.
But be that as it may, none of the black-hole scenarios currently up for grabs – not Jackson-Ryan, and not Jack’s update of it, the Vurdalak Conjecture, either – presuppose that the mini-black hole exploded at any time during or after the Tunguska event. For one thing, Stephen Hawking didn’t even publish the papers on primordial black-hole radiation that first raised the spectre of PBH explosion until well after Al and Mike’s Nature article (though I seem to recall Al telling Jack that preprints of Hawking’s results were already making the rounds back in 1973 – Jack’ll talk about that in Soapbox Seminar #3 or #4, I believe). For another, the PBH mass needed to produce the Tunguska observables are too big: PBHs, per Hawking, explode when they skinny down to about 10^14 g, or 100 million metric tons; J&R’s hole, as noted earlier, would have been a million times that.
Now, as to how much mass such a beast might absorb while cruising through the earth, the consensus seems to be not a whole lot. The PBH, even J&R’s monster, is going to be molecule-sized at most (and the updated version’s closer to atom-sized). So there’s just not enough of a capture cross-section to do any really serious gobbling. Not on one (80 minute?) pass straight through, anyway. Add to that the fact that the PBH’s outpouring radiation (temperatures in the millions to billions of degrees C, depending on what size you pick) is going to interfere with the infall, and odds are the total amount of matter consumed would be minuscule.
(Enjoyed your alternative Tunguska explanation VM, BTW!)
– Jk
The Krinov reference, once I found it, was anti-climactic to say the least, consisting essentially of a single sentence (Giant Meteorites, Pergamon 1966, p. 173):
…and that’s followed by a citation to: I. S. Astapovich, Meteorite Phenomena in Earth’s Atmosphere, Moscow, 1958.
Fortunately we can always fall back on Sekanina, whose monumental review of the literature on Tunguska (Zdenek Sekanina, “The Tunguska event: no cometary signature in evidence,” Astronomical Journal, 1983, vol. 88, No. 1, pp. 1382-1414) contains this passage (p. 1383):
I’m not skilled enough at the discussion board mechanics to manage a tabular format, but here’s a transcription of the content of Table 1. “Physical characteristics of the Tunguska event” as relates to “Explosion energy” (p. 1384):
…and the references are as follows:
Summing up then, these estimates range from 1 * 10^23 ergs = 2.4 megaton at the low end to a high of 1 * 10^24 = 23.9 megaton, with most of them falling somewhere in between.
LOL! – I’ve always loved that “Dr. Peter Venkman” shtick (though Bill Murray does it better, as I’m sure you’ll agree).
Seriously, sorry about the tardy response – I’m afraid your post got overlooked in the midst of all the more substantive discussion. But if you’re in earnest about wanting to talk to Jack, that’s easy enough to do:
Actually, “Doctor Jack” addresses the whole Ockham’s Razor issue in the latest Soapbox Seminar, posted today on <http://www.vurdalak.com>. See what you think.
(You may need to force your browser to reload the homepage to get the update.)
Interesting. So whoever-this-is’s method of addressing Occam’s Razor is to just decree that it’s irrelevant whenever any explanation is not quite complete. This is absolutely incorrect. I can exactly explain the Tunguska event by a Færie Conspiracy Hypothesis: A team of brownie lumberjacks very carefully cut down all the trees, and lowered them using winches into the radial blast pattern. Carbonation on the trees was added by dryads with eyedroppers of liquid carbon. The seismic activity detected in various parts of the world were added locally at each seismograph by oreids just under the detectors, the reindeer were all ritually slaughtered by pucks, and the observed fireball was produced by nixies shining sunlight into all the witnesses’ eyes with mirrors. A suitable elaboration of the Færie Conspiracy Hypothesis can explain any observed piece of evidence, and unlike the comet or asteroid hypotheses, it is consistent with all the data. The only argument against the Færie Conspiracy Hypothesis is Occam’s Razor. But whoever-it-is would tell us that Occam’s Razor doesn’t apply here, because there’s other evidence against all of the other hypotheses.
Jack decided to answer this one himself. (I know, I know – he doesn’t exist, but then, neither do I.) The response got kind of long, though, so with Chronos’s kind permission, I posted both Chronos’s question and Jack’s answer on the vurdalak website.
If you haven’t already read it, you might want to check out Spider Robinson’s most recent(?) book, Callahan’s Key – it stars Nikola Tesla and his Tunguska Death Ray.
Just a note to let the Tuguska thread-followers know that, here at the Vurdalak Conjecture website, we’ve been hard at work expanding one of our most popular features – the eyewitness accounts of the Tunguska Event. We’ve already got the Web’s single largest collection of Russian eyewitness accounts in English, and we’ve just added three new ones:
Kokoulin, agronomist from Nizhne-Ilimsk;
M. R. Romanov, peasant from Nizhne-Ilimsk;
N. N. Polyuzhinskii, observer at the Ilimsk Meteorological Station.
…with many more coming soon!
Some of the materials in this treasure-trove of testimony have never appeared anywhere in English translation before. To start sifting through the annals, searching for the one elusive clue that just might unriddle the “cosmic mystery of the millennium,” point your browser at:
… and then click on the “target: tunguska/witnesses” link in the side navigation bar.
(And, while you’re there, check out the mythical “Doctor Jack’s” latest Soapbox Seminar. It’s called “Where do Baby Black Holes Come From?” And, no, the answer’s not “from under a cabbage leaf.”
The answers you were looking for back in July have at long last just been posted in Jack’s 13th and final Soapbox Seminar <http://www.vurdalak.com>. Be interested in your thoughts.
