Jackson & Ryan Bite the Dust!

When we left off last time, the Jackson-Ryan hypothesis that the Tunguska impactor was a subatomic-sized primordial black hole was being buffeted from all sides.

Now, it’s important to remember that the international physics community already had their backs up over Jackson-Ryan — a knee-jerk negative reaction, maybe, to the amount of play the idea was getting in the mass media (what they call the Carl Sagan effect). So, once the Beasley-Tinsley and Burns-Greenstein-Verosub papers came out, all hell broke loose.

Mike’s memories of that time even include a memorable run-in with the Princeton professor who’d given black holes their very name — John Archibald Wheeler himself:

“A colleague there in Austin told me that John Wheeler was absolutely furious about this, and that he was fuming and foaming at the mouth over this ‘terrible idea,’ and how dare we have done such a thing? And so, a few months later, I saw him at a conference in Dallas, so he came up to me and said, ‘I’ve been hearing about this little black hole hypothesis in Siberia.’”

Rather than face any more frothing at the mouth, Mike told Wheeler about Beasley and Tinsley’s research on the missing exit-event:

“So I said to John Wheeler, ‘They did this experiment and there’s nothing there.’ And he said, ‘Oh, good!’ And then he said, ‘And now what you have to do is write all kinds of papers saying that this is completely crazy and that there’s no possibility that it’s ever correct, because if you don’t, in the future, the nuts will get hold of it and keep it going for a long time.’”

Well, Al and Mike never did get around to writing those “all kinds of papers” disavowing their original hypothesis, but decades later Al Jackson couldn’t help but look back and entertain a counterfactual:

“I’ve really wondered over all the years, if we had titled that paper differently, like ‘What is the Physical Effect of a Primordial Black Hole Hitting the Earth,’ instead of connecting it with the Tunguska Event … because we caught holy hell over proposing that it was the Tunguska Event.”

Holy hell, indeed. Before it was all over, even Carl Sagan hopped aboard the bandwagon. In the appropriately-titled “Heaven and Hell” episode of Cosmos, you’ll see Carl pointing out how “the records of atmospheric shock waves show no hint of an object booming out of the North Atlantic later that day.”[1] The no-exit-event objection, in other words.

What had started off as a debate over a new hypothesis was turning into a game of astrophysical pile-on.

Russian researchers, who sometimes seem to think like the Tunguska Event ought to be their own private preserve, routinely went ballistic at just the mention of the Jackson-Ryan hypothesis. In his book The Day the Sky Split Apart, astronomer and meteorite hunter Roy Gallant reports that our old friend Academician Nikolai V. Vasil’ev was still steamed about it two decades later, in 1992:[2]

“If Jackson and Ryan had bothered to acquaint themselves with the geophysical materials published in Russia and America before publicizing their fantastic idea, they most likely would never have proposed it. Evidently the authors, in their naiveté, supposed that in 1908 such a cataclysmic event as a black hole exploding out of the North Atlantic Ocean would have gone unnoticed. However, the population of the eastern regions of Canada, Iceland, and southern Greenland was significant. Those people published newspapers and had meteorological stations and observatories, and there were dozens of vessels in the open ocean. Furthermore, a tsunami would have been generated. Under these circumstances the event could not possibly have gone unnoticed.

“If professional scientists indulge themselves in such liberties, you can imagine how readily such science fiction notions will be eagerly and gullibly seized by the mass media … The sad results are disoriented public opinion and complications in the further study of this complex natural phenomenon.”

It wasn’t only the Russians, of course. We’ve already seen how Tom Gehrels, the principal investigator for Operation Spacewatch, went out of his way to lump Jackson and Ryan’s “mini-black hole” hypothesis in with UFO crash-landings as “nonsensical speculation” as late as the mid-nineties.[3]

But they were all beating a long-dead horse. As far as the world physics community was concerned, by the late seventies the Jackson-Ryan conjecture had already crashed, burnt, and got shoveled over with dirt. Tunguska researchers could breathe a sigh of relief and go back to fighting over meteorite this, and cometary that.

Even Al Jackson and Mike Ryan pretty much forgot about it. It sure looked like the end of the line for the primordial black hole impact theory of Tunguska. As Mike puts it:

“It died a natural death and so no one has ever said anything about it anymore.”

Not to differ with Mike, but I’d like to say something more about it.

In particular, I’d like to try and convince you, in the rest of this Soapbox Seminar series, that — be it right or wrong — the Jackson-Ryan hypothesis isn’t “naive,” or “science fiction,” or “nonsensical speculation,” or any of the other labels folks have pinned on it over the years. That — right or wrong — it’s no less scientific than any of the more widely held theories. And that, as Burns and his friends pointed out, in a situation where “all possible explanations must be seriously considered and … no explanation can be discarded merely because it has a low probability of occurring,”[4] it might just possibly be right.

But to see how it might be right, we’ve first got to take a closer look at those primordial black holes.


All quotes from Al Jackson and Mike Ryan are courtesy of Albert A. Jackson, IV and Michael P. Ryan, Jr., as recorded at the Johnson Space Center Amateur Astronomical Society meeting and Singularity launch party, November 2004.

[1] As repeated in Chapter IV of Carl Sagan, Cosmos, Random House, 1980.

[2] Roy A. Gallant, The Day The Sky Split Apart: Investigating a Cosmic Mystery, Atheneum, 1995.

[3] Tom Gehrels, “Collisions with Comets and Asteroids,” Scientific American, March 1996, pp. 54-59.

[4] Jack O. Burns, George Greenstein, and Kenneth L. Verosub, “The Tungus Event as a Small Black Hole: Geophysical Considerations,” Monthly Notices, Royal Astronomical Society, vol. 175 (1976), pp. 355-357.