Exploring abrupt climate change induced by comets and asteroids during human history

Open Letter: Napier on Defant and the Joe Rogan podcast

Bill Napier sent the Tusk a note regarding Joe Rogan’s unforgettable debate-style podcast on the Younger Dryas Boundary Hypothesis. Bill’s message is posted below my rant here. His informed correction of Marc Defant’s self-styled skeptical authority on comets is priceless and instructive.

A cultural genre of all-purpose professional “skeptics,” like Defant and Shermer, have emerged since James Randi kicked off their gig forty years ago. Like many fashions, professional skepticism served a role and had its day, but then devolved into a vanity-infested quasi-intellectual troupe of know-it-alls PhD’s — in something — who nonetheless are regularly consulted by the media and listened to concering all things “science.” (Somehow “science” persisted for 400+ years before their preening website and yearly convention).

As a generalist myself, and an expert in nothing, the Tusk has no problem with generalist commentary and skepticism. I consider myself a skeptical generalist and my wife would agree. But experts in a particular subject  — volcanology in Marc’s case — should exhibit and disclose some humility before and perhaps after they harrumph, guffaw and dismiss the long-published data-driven conclusions of expert workers in other subjects — especially when the subject is controversial and concerns a worldwide threat. If they do not declare their relative ignorance, they are “dangerously misinformed” — precisely what they purport to eradicate.

Defant showed zero humility and spoke of comets with the familiarity of a volcanologist. He should be ashamed to dismiss the work of Bill Napier, Fred Whipple, Clube, Asher, Palmer, Steel, etc. etc etc, without explaining or perhaps even knowing of their work first.

Dafant makes a complete hash of comet science. He tells us that the comet impact hypothesis is incorrect because comets break up only under the relatively short-term influence of a planet (his example is “Shoemaker-Levy 9,” a profound recent event for which he cannot recall the name) or the relatively momentary drag of a planetary atmosphere. He may or may not know it, but Dafant’s received wisdom (in keeping with his fellow Skeptic Mark Boslough) is eclipsed by the work Napier.

The published truth is horrifying. Some comets begin to disintegrate when they are thrown into the inner planetary system, generating streams of debris for millennia. The Taurids being a major complex of such material. They are increasingly less noticeable when they degrade, but still dangerous in proportion to the “spread” of the debris, the size range of the objects, and the approach of our planet within the stream.

As Napier and his colleagues have maintained for decades, and all but proven, a monstrously large comet entered our solar system roughly 20,000 years ago, began disintegrating, and left a stream of debris we encounter annually ever since. 8000 years later, or ~12,875 years ago, we orbited through a particularly rough patch of the Taurid stream that caused world-wide doom, with pieces and parts of all sizes — but still a fraction of the original beast — crashing into mother earth and causing extinctions. Other impacts of various sizes have occurred before and after that event depending on our trajectory as we pass through the lumpy haze of the relict comet around late June and Halloween June each year. The comet did not disintegrate in the atmosphere or because of our planet’s gravity.

Under a cloudless night sky outside Flagstaff, Arizona, I once asked Mark Boslough, a fellow-traveler of Shermer and Defant, what he thought of Whipple’s clear evidence and Napier’s concern regarding progressively disintegrating bodies in short-period orbits. Boslough said he did not know what the hell I was talking about. Neither does Defant.


I’m not into lost civilizations or sacred geometry, but I am into cometary science and have a few comments on this aspect of the recent Joe Rogan podcast. In a weird inversion, Graham Hancock and Randall Carson were much closer to orthodox science than Marc Defant and Michael Shermer.

Marc Defant told us that “the comet guys are getting hit pretty hard,” but alas, he backed this up with a blatantly wrong description of comet evolution. Comet splitting occurs spontaneously, doesn’t require tidal disruption a la Shoemaker-Levy 9, and has nothing to do with breakup in the terrestrial atmosphere. It can occur anywhere along the orbit and is the dominant mode of comet disintegration. The mass fraction lost in a splitting event is of order s/R, R the radius of the comet in units of 10 km with s generally in the range 0.7 to 1%, depending on the model. The splitting frequency depends on the perihelion distance, and for a comet in an Encke-like orbit it amounts to one such event every 3 or 4 revolutions (orbital period 3.3 years). In the case of a 100 km comet in such an orbit, 15% active surface, fragments amounting to a mass several times 10**17 gm will detach during each splitting event. Hundreds of such events are expected over the lifetime of the comet. The material spreads out along the orbital track, but an encounter with say 10**13 gm of fragments is possible and is energetically equivalent to running through 1000 Tunguska-sized fragments. Long dormant periods are also possible for comet fragments. These can last for up to 40% of the active lifetime of the fragment, during which it looks like an asteroid.

I was glad to see Randall Carson mention Fred Whipple as a pioneer of Taurid/Encke studies, preceding the “British school”. All the cometary astronomers of that generation (Whipple, Sekanina, Kresak, Stohl) realised that the Taurid complex was debris from an exceptional comet, and recent large-scale surveys of the meteor sky (both radar and visual) have confirmed and quantified the work of these early pioneers. These surveys yield direct observational evidence for the hierarchical disintegration of an erstwhile exceptionally large comet in a short-period, low-inclination, Earth-crossing orbit. The celestial mechanics calculations of Steel and Asher provide the timescale: the comet was around and disintegrating at least 20,000 years ago, maybe much longer.

I should mention that, although the “British School” have a substantial literature and about two centuries of combined experience in comets, the above is distilled from a very much wider group of contemporary astronomers in the Americas, Russia, Europe and elsewhere.

Marc and Michael seem to have been misled by unrefereed nonsense from a few people with no expertise or track record in cometary dynamics, and ignorant of its extensive, long-running literature. A little skepticism might have been called for!

A final comment: I agree with Malcolm LeCompte that the issue may not be as simple as a single big impact. But platinum and iridium are created in, and ejected from, supernovae and were present in the protoplanetary disc within which comets formed; these elements are diagnostic of an extraterrestrial input but not particularly of asteroids.

We don’t need a rubble pile asteroid (in any case we’d see the debris and we don’t). A meteor hurricane, with imbedded Tunguskas, may be enough.
Whether we’re dealing with one or two very large impacts, or a bombardment of smaller ones, or nothing at all, is a matter for the Earth scientists. But if the evidence on the ground calls for an ET event 12,900 years ago, the comet guys — the real ones — can supply it.

Bill Napier

22 Responses

  1. On the topic of comet impacts, I’ve been trying for several months now to get someone from academia and the alternate history elite to look at my research in hopes of receiving critical feedback on my discovery of an ancient comet impact in the Caribbean region.

    I have found solid evidence, after reviewing several archival NASA impact simulations of Shoemaker-Levy 9 videos that can be found on NASA’s YouTube portal. I have successfully confirmed my hypothesis about the comet impact in the Caribbean and not only can I prove that the impact happened, I can also prove how it effected much more then just this area. I’m talking, much, much, much more.
    I am seeking verification of my discovery by any and all that wish to comment on my research. “Silhouette of A Comet” is a short video presentation of my research, still in progress, that I’ve posted on YouTube showing some of my findings. I will continue to push for this discovery to be revealed to everybody. I believe this could be the smoking gun that our community of alternate history believers has been looking for.

  2. The comment below was submitted by Tusk favorite Herm Burchard, but not posting for reason. I’m posting now until we work the bug out.

    Dear Bill,

    since George was kind enough to post my post my Younger Dryas Comet paper after it appeared publicly last Feb 27, 2017, I believe that I deserve consideration of what I believe is my definitive proof, albeit circumstantial, of a comet impact ~12,900 BP that excavated many km deep into bedrock in the Great Lakes region, in several fragments, and widespread damage on the Northern Hemisphere including a Laach impact in the Eifel Mountain area near Cologne, Germany. The impact was slant and expelled ejecta to the Atlantic Seaboard, creating the Carolina Bays, in the way analyzed by Tim Harris and later verified by others. Instead, you and others simply ignore my work. — I have had two professional geologists, who I knew have an interest in impact matters, comment favorably on my paper as did one of Richard Firestone’s co-authors in addition to George. As an applied mathematician I took courses in physics and astronomy and have studied geology since teenage (now 82). Geologists mostly despise cosmic impacts on our usually solitary planet, which they prefer to see that way, unmolested by nasty comets, and mostly are ignorant of and outright deny the frequent occurrence of such events, as well as their effectiveness in causing impact volcanism, which I have proved in another geology paper that is quoted in the one posted by George on his marvelous Tusk site, etc, etc. I’ll stop here . . Sincerely,

  3. Mr. Burchard ,

    Please define what a “Laach impact” is for the uninformed.

  4. Trent,

    the Laach is a lake near Cologne at map coordinates 50.416667N, 7.266667E, more commonly “Lake Laach.” A famous medieval monastery is on the shore. There was an eruption at about 12,900 BP at nearly the same time as the Younger Dryas Comet (YDC). Please see my YDC paper, the Conclusions. Thanks for asking.

  5. Laacher See is a large maar in the middle of the Eiffel Volcanic Field in Europe. Dates line up nicely to connect to the YD event, but to the best of my knowledge there is no impact crater in the region. There is OTOH a significant layer of pyroclastic materials, volcanic ash, and associated debris. Erik Klementi has some great photos. Could one cause the other? Unknown, though maars happen when quantities of water interact with magma near the surface, which is most certainly something that could have been triggered by seismic activity associated with the impact events. Unfortunately we don’t have any evidence of that either. Interesting idea. Keep on looking. Cheers –


  6. You need to get into the impact simulators and play a while.

    You are proposing a pair of impacts – one north of South America at the eastern end of the Caribbean Plate and one south of it at the end of the Sandwich Plate. Diameter of both curved portions are in the vicinity of 600 km. Tectonics opened up the southern portion when Gondwana broke up some 180 Ma. To the north, the Caribbean Plate started moving some 80 Ma. These dates are important as the impact event dates must be younger than them otherwise the impact effects would show up on the continents rather than in the oceans.

    If you play with the simulators, you find that it takes a body 40 – 50 km in diameter moving at 50 kps to create a crater that large. The KT impactor was only 10 km or so and may or may not have been a comet, but it wiped out a lot of life. Something 4-5 times that diameter would cause a worse extinction event and we haven’t seen one that large that recently.

    If you poke around the tectonics / volcanology blogs a while, you find that subduction zones are curved more times than not. I think you are confusing a curved subduction zone with an impact structure. Cheers –


  7. Agimarc: The Laach maar is the impact crater. This is the site of an eruption that bears all the hallmarks of having been caused by an impact explosion presumably from the YDC, including a large butterfly ejecta pattern covering Skandinavia. Please see my two papers & update or adjust your geological perspectives to the new reality of impact volcanism. Here are the links to my two papers Nov 2016 in OJPP and Feb 2017 in OJG, also posted by George on the Tusk: YDC paper posted on Tusk and Yellowstone Impact.
    Thank you.

  8. I think we’ve had this discussion after posting your 2016 paper. Wasn’t convinced then. Still am not.

    Just because there is a circular hole in the ground, does not mean that hole is an impact crater. Maars are numerous volcanic artifacts worldwide. While on the large side, the LS is not particularly unique. Big sky, little bullet may work for the LS. It will not work for all the other maars out there.

    I think the key is the relationship between the LS pyroclastics / tephras with the YD microspherule / nanodiamond layer. If the YD layer is thin and located above, below, or somewhere in between layers of volcanic debris, the LS was not caused by an impact. If the YD layer and the LS layer is well mixed and broad, you can start making a case for impact involvement. Haven’t seen any of that yet, though I may be missing something. Cheers –

  9. Right, those aren’t impacts, though the Scotia plate one is certainly a teaser. The two plates are amazingly alike, though. Both are arcs in the larger sense that sweep eastward. The Scotia plate seems to have some uplift in the center of the island arc at the eastern end, but it’s not centered, so that is a strike against it, IMVHO. (I am not aware of uplifts that are not centered.) There is also another arc/circle near the center of that large arc, and that also lacks a center uplift, though there are some elevated portions.

    The Caribbean plates arc has uplift in the middle of it, but it is actually a straight-as-an-arrow ridge going completely across the plate. That is not something that is going to win over any crater experts as an impact feature.

    I agree with you, agimarc, that it is some sort of tectonic movement. They SEEM to have experienced the same sort of formative years, with those island arcs at the eastern end of each. The Scotia plate has an ocean trench that reaches deeper than 7800 meters, which suggests the Scotia plate is subducting the Atlantic plate and lifted the islands along the leading edge.

    The Caribbean plate island arc seems to have no such trench ahead of it that might have lifted it, but at least on Google Earth it looks like something weird happened. That lack of a trench seems to set the two arced plates apart. It has an ocean trench (also around 7500 meters deep), but the trench is along its northern flank, not at the lead end.

    Both arcs are considered “convergent” faults/plate edges.

  10. I’ve got a lot of respect for the comet guys. Our latter day neo-catastrophists.

    Love ya, Bill!

  11. SteveGinGTO, please see my above response to agimarc.

    You are correct that, “the two plates are amazingly alike.”

    Allow me to default to “Gibb’s Law, Rule #39: There are no coincidences.”

    *** “The Caribbean plates arc has uplift in the middle of it, but it is
    actually a straight-as-an-arrow ridge going completely across the plate.
    That is not something that is going to win over any crater experts as
    an impact feature.”

    I’m not worried about winning over a “crater expert.” All I care about what can be proved utilizing science and physical evidence. There is credible evidence in the computer simulation that changes the way craters and impact zones will be approached from here after. I believe because of the modern tools we have access to and the experience in my career has aided me in being able to see the similarities between the computer simulation and the natural land formations.

    The “straight-as-an-arrow ridge” you speak of can be found in other NASA pictures of impact “craters”

    Remember this was an extreme angled impact, smashing the sea floor and possibly pushing down that sea bed in what is now considered the “Caribbean Plate”. I’m convinced it was a comet as I will reveal in my full documentary upon completion, the evidence is too obvious to deny. I leave you with an additional comparison jpeg image of FL and surrounding sea trenches and islands.

    Thank you for your feedback and time.




  12. Howdy Huey –

    Whatever your data might be, it still doesn’t deal with the very real issue of a pair of massive impacts on either end of South America, the southern one more recent than 180 Ma and the Caribbean one more recent than 80 Ma. The impact calculators put the body in the 50 km diameter range. Best I can find, nothing that large has hit the earth more recently than the last 3 billion years, perhaps as far back as the Late Heavy Bombardment 3.9 billion years ago. Generally when something that large hits, you end up with an extinction event. The largest extinction event over that period was the K – T event tied to the Deccan Traps and the Chicxulub impact at 65 Ma. That body is in the 10 km range.

    The only other thing I’ve come across is the notion that large impacts in oceanic plates create Large Igneous Provinces. There is a suggestion that the Ontong – Java plateau formed 120 Ma was the result of an impact event of a 20 km diameter body. The eruptions put perhaps 16 x the volume of the SIberian Traps on the ocean floor. But we don’t see any massive lava outpouring near either curved center.

    Don’t mind the discussion. Not convinced that we’ve had a relatively recent impact that large (50 km body) as recently as 180 Ma and 80 Ma, much less two of them without either a massive lava outpouring or extinction event. Cheers –

  13. Hello and Happy Thanksgiving.

    I wanted to update you with some more of my research:

    In the posted jpeg you will see in the inset on the left, a freeze frame from NASAs 1994 computer simulation of comet Shoemaker Levy 09 impacting into Jupiter. On the right is the corresponding, what I’m calling a “fingerprint” of a comet impact into the Caribbean Sea. https://uploads.disquscdn.com/images/af1bc1d078b770d4ad701bfd3b065bd9f39b261a33d5930de5bbf99e481342ca.jpg

    I have compared several frames of NASAs computer simulation and can confidently say that this is just the tip of the iceberg of my research. Thanks for the interest in this subject.

  14. After five years (I now am 87) this suddenly came back psted by ResarchGate and this comment site still appears to be alive on May 4, 2022, amazing. Looking thru these ancient “still not covinced” remarks, I feel constrained to explain a little further: THE TWO-STAGE COMET IMPACT THEORY BASED ON EXPLOSIVE VOLCANISM AS EXPLAINED BY STEVE SPARKS.
    ….He is a Vetlesen Award winner, aka Nobel of Geoscience. His contribution is in the influence of volatiles on explosive volcanism, explained in over 300 published peer-reviewed articles. He gave a demonstration in the 1990s on BBC, how the magma chamber created by the impact in the uppper mantle leads to “resurgent calderas.” He is not interested in impacts, like most geolotists he has his eyes on the ground, will not look up into the heavens from where comets fall on every crater-strewn spherical planetary body. The magma chamber, after each resurgnet explosion, refills from surrounding mantle rocks with volatiles. Ample H2, CH4 (methane) and higher hydrocarbons are in the mantle from the primitive solar nebula, as in all other dense star-birthing clouds allover the univese. Petroleum engineers read my explanation in Bennhy Peiser’s old CCNet (?) impact-oriented newsletter, where I explained this. The Siva crater of Bombay-Mumbai (400 km), Seychelles the Western Half drifted away from the Indian subcontinent. Also the Ames Crater in Major County which created one of the richest oil-fields. Petroleum engineers read my explanation about the impact “fracturing” crystalline basement rocks so the hydrocarbons can seep up. Methane synthesized into higher C-H chains in the high temperature high pressure regime of the mantle. Petroleum engineers styled it “fracking,” and decided to let the human power do the comets work.

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