Tunguska black hole reconsidered

Cecil's Columns/Staff Reports
1

Cecil –

In your generally well-informed February '03 column exploring the cause of the cataclysmic Tunguska Event of June 30th, 1908, you note the following possible explanation in passing:

QUOTE:
5. It was a black hole. Proposed by two American scientists in 1973, this theory is dismissed by most other investigators as hopelessly naive.
:UNQUOTE

Well, Al Jackson and Mike Ryan (the “two American scientists” in question) might have been wrong, maybe – but “hopelessly naive”? This particular characterization seems to have been drawn from the remarks of Academician Nikolai Vasil’ev, as quoted in Roy Gallant’s book The Day The Sky Split Apart (Atheneum 1995, p. 122). And Vasil’ev’s only substantive objection seems to have been the same one put forward by Bill Beasley and Brian Tinsley back in 1974. Namely, that the so-called “exit event” predicted by Jackson-Ryan – an equally cataclysmic explosion as the black hole erupted up out of the North Atlantic later that same day – never took place.

But the past three decades have seen enough advances in black-hole studies (Hawking radiation and “black monopoles,” to name a couple) to raise the ghost of a chance that Al and Mike might be vindicated yet (and, trust me, that might not be a good thing!).

In any case, there’s a new website <http://www.vurdalak.com> about to fire up on Wednesday, June 30th – just in time for the 96th anniversary of the Tunguska Event. It’s devoted to a detailed re-examination of the Jackson-Ryan hypothesis, and a new spin on that old theory called “The Vurdalak Conjecture.”

So, check it out, Cecil. It might not convince you, but it at least promises to enlighten and entertain. – And it is the “Straight Dope”!

Jenkoul

2

Here is a link to the column in question, as is customary on the SDMB, Jenkoul .

http://www.straightdope.com/columns/030228.html

And your regerence to a new website is intriguing----and possibly self-promoting. :dubious:

3

I’m a big fan of the Tunguska Meteorite (I wrote an unpublished article on it many years ago), and it never ceases to amaze me.

IIRC, Jackson and Ryan stated that their suggestion was somewhat “tongue in cheek”, and never intended it to be taken completely seriously. There was an article in a Geophysics journal shortly afterwards that argued that, had a mini black hole gone through the earth, the gravitational perturbations and tidal forces would have produced unmistakeable seismic events. There are plenty of seismic rtecords from that day (I’ve seen reproductions of them, from all over the world), and there’s nothing beyond what you’d expect.

Everyone with a pet theory seems to look to the Tunguskla event as a verification of it. Three different groups at three different times, proposed that it was due to an antimatter meteorite, for instance.

The evidence that it was due to an ordinary clump of matter, and probably a piece of comet, is pretty good – stony and glassy micrometeorites were found in an ellipsoidal footprint tailing off to the northwest of the site. Even Kulik’s last expedition (circa 1930s) found what may be small fragments. There was certainly another meteorite fall on that same day, sonme distance away (although books and articles on the topic seem unaware of this), and there was the injection of a very large quantity of meteoric dust into the atmosphere of Europe, caused extremely bright “noctilucent clouds”. One could read newspapers at midnight outdoors by the light. Furthermore, the event coincided with the passage of the Pons-Winnecke comet, as many meteoric events do.

4

If you’re suggesting that the Tunguska object might have been a black hole which evaporated completely at some point between its entry and its exit (thus explaining the lack of an exit event), that would be exceedingly unlikely. Final evaporation is a very quick event, and one would have to postulate that after the however-incredibly-long this thing spent travelling through space, it just happened to evaporate just as it exactly happened to be passing through a very small region with much higher density (and hence available fuel) than deep space.

But the lack of an exit wound is not the primary reason for discarding the black hole hypothesis. Rather, it’s because of Occam’s Razor. Even without the corraborating evidence for meteoric activity mentioned by CalMeacham, we are certain that comets and meteoroids exist in great abundance in our neighborhood, and the hypothesis that the impactor was a small comet or large meteor explains the observations about as well as the black hole hypothesis does. Since both have about the same explanatory power, we choose the one which requires less assumptions on our part.

5

Going on the not unreasonable assumption that the OP is the owner of the linked website…

Eh, I’ve now visited the website in question, and even allowing for the fact that it’s not completely “installed”, still…

Mere sweeping generalizations and dogmatic statements that “this is how it MUST be” do not “make a case”. You need stuff called “evidence”.

Also…WTF is up with this, at the end of the first article?

You want me to register to read the rest of your website? Sorry, not interested.

And, sorry, but I really have to question this:
http://www.vurdalak.com/whoisjack/jackadler.htm

So, you’re supposedly a physics professor somewhere–but your department head won’t let you talk about your “alternative” Tunguska theory in public? Sorry, but I find that VERY hard to believe, almost cartoonishly tinfoil hat paranoid. It’s not that wack a theory, for one thing–as you yourself point out, it’s already been mentioned, 30 years ago.

Now if you were going to postulate that reptilian aliens created it, then I’d worry about my boss finding out. But a black hole as causation is a fairly mainstream explanation, at least as compared to “An alien UFO blew up!” or Nicolas Tesla being involved, etc.

(And thus I’m assuming that the photo of “you” in an Indiana Jones costume isn’t “you”, either, since there would be a danger that your Evil Department Head would recognize you.)

And:

No, your “seminars” are your plain and unvarnished theory. If they were the “truth”, you’d have “evidence” to back them up.

Proof.

Until you’ve got “proof”–which you must know, you bein’ a physics professor and all–all you’ve got is a “theory”.

6

The other theory is that the Tunguska Event was a test of an early (1908) prototype of a 1920’s Style “Death Ray” (Cite: S. Robinson, Callahan’s Key, pp. 207-8)

:smiley:

7

Actually, there’s one whacko theory that the Tunguska event was the result of aliens for Cygni 61 replying to what they thought were Earth signals (but which were actually radio emissions from the eruption of Krakatoa), so it was really a Nineteenth Century-style Death Ray. (Besides, the damned thing was in 1908 – it had to predate the 20s).

This idiocy actually got two columns in Time magazine. Must’ve been a slow news week.

8

I just visited the site – Bozhe moye, he cites F. Yu. Zigel and Kazantsev!
If you want the Straight Dope on Tunguska, get hold of Yevgeny L. Krinov’s books Priciples of Meteorics and Giant Meteorites. Both have been translated into English and published by Pergamon Press. Krinov’s credentials are impeccable – he was on a number of the expeditions that Leonid Alexeyevich Kulik organized to the site in the late 1920s and early 1930s. You might also dig out translations of Kulik’s own reports. Some were translated by the journal Popular Astronomy and others appeared in one or another of the volumes of the Izvestiya Akad. Nauk SSSR. There was also a decent popular paperback published by MacFadden Books entitled The Tungus Event (By Furneaux?)

But don’t get Baxter and Atkins’ The Fire Came Down, which ignores all theoriesw but the Exploding-Alien-Spacecraft version.

9

All that you need to note is one frame of business that shows up on each page.

Emphasis should be placed squarely on “crank”.

10

Point of order… when conversing in a written medium, it’s not necessary to write out the air quotes. Just use the same quote marks you used two paragraphs earlier.

Thank you.

11

> Also…WTF is up with this, at the end of the first article?
> You want me to register to read the rest of your website?
> Sorry, not interested.

Apologies if I gave that impression. There is no “rest” of the website, no hidden pages, etc. – but there will be constant updates. In my understanding, registration is just a convenient way of receiving notification when the next “soapbox seminar” gets posted. You can achieve the same effect by checking in manually every couple weeks or so.

12

If you want the Straight Dope on Tunguska, get hold of Yevgeny L. Krinov’s books Priciples of Meteorics and Giant Meteorites. Both have been translated into English and published by Pergamon Press. Krinov’s credentials are impeccable – he was on a number of the expeditions that Leonid Alexeyevich Kulik organized to the site in the late 1920s and early 1930s. You might also dig out translations of Kulik’s own reports. Some were translated by the journal Popular Astronomy and others appeared in one or another of the volumes of the Izvestiya Akad. Nauk SSSR. There was also a decent popular paperback published by MacFadden Books entitled The Tungus Event (By Furneaux?)

But don’t get Baxter and Atkins’ The Fire Came Down, which ignores all theoriesw but the Exploding-Alien-Spacecraft version.
[/QUOTE]

You might also take a look at Roy Gallant’s The Day The Sky Split Apart: Investigating a Cosmic Mystery (Atheneum 1995). It’s written for “younger readers,” but manages to pack a good deal of useful information in nonetheless. Beyond that, if you want anything recent (Krinov’s English version dates from the mid-sixties), you’ve got to go to the journal articles: Luigi Foschini, V. Bronshten, Zdenek Sekanina.

Fully agree on Baxter and Atkins. Check out James Oberg on that topic – at <http://www.jamesoberg.com/ufo/tungus.html>.

13

Dear Duck,

If you’re referring to the seminar’s first paragraph, I think you’ll find on a second reading that Jack has his tongue in his cheek here – in response to the truly “sweeping generalizations” in the Tom Gehrels epigram.

-J

14

Actually, the evaporation scenario is a total non-starter. In his 1975 article on “Particle Creation by Black Holes” (Commun. math. Phys., 43, 199-220), Stephen Hawking estimates that “in the last tenth of a second the energy released [from an evaporating primordial black hole] would be of the order of 10^30 ergs.” That works out to about 100,000 times the total energy release due all the earthquakes in a given year. The Tunguska Event was a good six to eight orders of magnitude less.

15

I believe you’re referring to Jack O. Burns, George Greenstein, and Kenneth L. Verosub’s “The Tungus Event as a small black hole: Geophysical Considerations” (Mon. Not. R. astr. Soc., (1976) 175, pp. 355-357). Jack deals with that objection in a subsequent column; not to steal his thunder, but here’s a preview.

Burns et al. account for the entire Tunguska energy release in terms of the kinetic effects of the supposed black hole’s mass on its passage down through the atmosphere. In work cited elsewhere in this thread, E. L. Krinov estimated the Tunguska blast at from 10 to 40 megatons; working backward from that yield gives you a lot of mass – anywhere from a hundred trillion tons on up. No question but that a primordial black hole that big would’ve produced the results computed by Burns et al.: “several thousand simultaneous earthquakes” as the hole passed through the earth, not to mention leaving behind a disk of fused rock and soil up to 4 kilometers in diameter at the impact site. Any of which would’ve been pretty hard to miss.

But it turns out that mass may not be the only way to achieve Krinov’s blast effects…

16

LOL! I’ll suggest that to Jack. :slight_smile:

17

I suspect Chronos is already broadly aware of this. After all, it’d be quite something if the energy release matched that involved in Tunguska.

18

Indeed. But firstly, one cannot put a hard number on the energy released in the last stage of evaporation, since there is no clear boundary to define the last stage (a tenth of a second is a nice convenient human-sized time interval, but it doesn’t mean much to a black hole). And secondly, while I do know rather a good deal about black holes, I don’t know much geology, and it seems plausible to me that a release of even that much energy in the core of the Earth might go relatively unnoticed here on the surface.

Frankly, to have a real discussion here, we’re going to need more information. I can’t begin to address a hypothesis which hasn’t yet been presented, and the section of that site on the Vurdalak Conjecture itself is not yet posted. If the Conjecture isn’t that the hole evaporated inside the Earth, then what is it? A zero-temperature extreme Reissner-Nordstrom hole, electromagnetically captured in some way by the Earth? A magnetically charged hole? A super-extreme hole of some sort? Really, there’s not all that much you can vary a black hole. What are you proposing new about this object?

19

Well, Unitconverter <http://online.unitconverterpro.com/fnenergy.html> reckons there’s 4.18410^25 ergs to the gigaton. Rounding up to 1.010^26 still makes 10^30 ergs roughly equivalent to 10,000 gigatons.

10 K gigatons seems like an awfully big explosion to go unnoticed, even if (especially if?) there’s 4,000 miles of rock and molten iron between us and the epicenter. But I confess, I don’t know either. I’ve asked Jack, though.

Your points are well taken. I would have to agree that a full-blown discussion of the Vurdalak Conjecture would be premature, given the dearth of information at this point. And, frankly, it wasn’t my intention to launch one here (I was just responding to Cecil’s original column).

In a way <www.vurdalak.com> is the discussion you’re looking for. I know it’s a slower “discussion” than you’d like, but the journey is paced to give the rest of us a chance to keep up. And sometimes the journey can be its own reward.

Best,
Jenkoul

20

What’s the possibility it was a chunk of anti-matter? IIRC there was a bit of evidence pointing toward this, something about elevated levels of some metal in the sediments that year.