Thread by @MarkBoslough

As I promised yesterday, I’m going to start addressing the specific scientific claims of the #BiblicalArchaeology paper on #TallElHammam, just published in Scientific Reports @SciReports which I will tag #TEHburst from now on. (Art credit: Don Davis)

There are supposedly 17 lines of evidence. Given that I have a day job, I’d be lucky to finish by mid-October even if I debunked one every day. But this is as much about entertainment as it is about enlightenment so I expect some diversions & do-loops.

I think it’s the backstory that will keep everyone engaged & entertained. So I will also alternate with human interest stories & fun threads with history & anecdotes. I’ll try to continue until I finish or everyone loses interest, whichever comes first.

Twitter is not a peer-reviewed publication where everything is vetted & corrected before publication. I have already made mistakes & surely will again. When I goof I will try to make corrections as I go along since tweets cannot be edited.

Corrections so far: 1) The paper was in Scientific Reports, not Nature. According to @Nature, “Scientific Reports is an online multidisciplinary, open access journal from the publishers of Nature". 2) The first citation was to the book of Genesis, right there in the abstract.

Clarification: One #TEHburst enthusiast has already accused me of ad hominem. In science & other fields we assess competence & credibility when hiring, judging proposals, tenure, awards, research, etc. CVs & history are relevant. Recitation of facts is background, not ad hominem.

The first technical items I want to address are 1) our understanding of the Tunguska airburst, and 2) shocked quartz. But that requires more backstory discussion. I won’t go deep. You can read the peer-reviewed literature for that. This is Twitter.

In June, 2008, I attended an international conference in Moscow called "100 years of the Tunguska phenomenon: past, present, future.” Here’s my title slide. I was presenting my then-controversial claim that the Tunguska explosion was much smaller than previously thought.

Here’s my 18th slide, showing my animation of a 15 Mt airburst at the best-matching entry angle of 18 degrees leading to a contact airburst, in which the high-temperature explosion products would reach the surface. I estimated that an airburst yield of 3-5 Mt was a better match.

Here’s #TEHburst figure 53, a more recent, higher-resolution, and prettier version of my 2008 simulation. I’m flattered that the authors seem to like my lower-yield Tunguska estimate. Not everyone does.

For example, my collaborators & colleagues who model asteroid airbursts at NASA Ames still think it was bigger. sciencedirect.com/science/articl…

When my employer at the time put out a press release highlighting my conclusions in late 2007, it was somewhat controversial & not immediately accepted.
I'd just published it & it was based on presentations I’d given at a couple conferences that year.
cfwebprod.sandia.gov/cfdocs/CompRes…

Because of the hoopla surrounding the 100th anniversary of Tunguska in 2008, Discovery Channel was going to shoot a documentary there. They wanted to feature 3 different scientists with 3 different out-of-mainstream ideas. This was the same formula as the 2006 BBC shoot in Egypt.

For Tunguska the other subjects were Jason Morgan & Gunther Kletetschka (now a #TEHburst coauthor). Jason thought it was what he called a “Verneshot” volcanic explosion. Gunther was there to argue for a “mirror matter” encounter (something I admit I still don’t understand).

I met Gunther & Jason at the Domodedovo airport in Moscow, where we were catching a redeye to Krasnoyarsk which would be our transfer point to Vanavara and on to Tunguska. (photo: Gunther & his son Karel arriving in Ванавара).

We weren’t the only oddballs on this pilgrimage. There were also five members from the “Holocene Impact Working Group” who believe that the flux of impacts is orders of magnitude higher than the astronomical evidence and cratering record indicates.
tsun.sscc.ru/hiwg/hiwg.htm

And there was an Italian group led by Luca Gasperini, who'd just published a very controversial paper claiming that Lake Cheko (downrange from the airburst area) was an impact crater. I’d gotten to know the Italians in Moscow and they were a lot of fun. onlinelibrary.wiley.com/doi/full/10.11…

And there were also a lot of Russians from Tomsk, who’d been doing fieldwork at Tunguska for decades. More on that in a future thread.

We all had the first day to explore. I thought I would tag along with Jason who wanted to collect samples, but I became skeptical when he started picking up what I considered to be random rocks, what geologists refer to as “floats” which could be from anywhere.

My position on the Dunning Kruger fieldwork scale wasn’t enough to be confident, but it was enough think this was a red flag. Geologists can’t be certain where float comes from. They want outcrop. So I spent the rest of my time tagging along with Gunther (more on that later).

I saw Jason a couple years later at the @theAGU fall meeting that December in San Francisco.
ui.adsabs.harvard.edu/abs/2010AGUFM.…

He subsequently coauthored a paper claiming shocked quartz in samples from this location (I don’t know if it was from float or outcrop). sciencedirect.com/science/articl…

Ironically, Jason didn’t think it had anything to do with the Tunguska airburst, but was evidence for his Verneshot hypothesis for the Siberian Traps. It was his opinion that an explosion could create shock waves strong enough to generate planar deformational features in quartz.

This directly contradicted Gene Shoemaker admonition: “volcanic eruptions are decompression events in all cases”. I remember him saying this at LPSC to those who attributed the Izett & Bohor discovery of shocked quartz at the K/T boundary to volcanoes. adsabs.harvard.edu/pdf/1986LPI...….

It was around this time that I wrote up these new findings and the significance of shocked quartz which was the evidence that convinced many colleagues of the Alvarez hypothesis. See Boslough, M.B. (1987) Quartz grains shape new impact theories. Geotimes 32 (6), 31-33.

Gene was both wrong & right. Volcanic eruptions make compressional shocks (phreatomagmatic explosions are analogous to thermal detonations that can cause reactors & foundries to explode). But they aren’t under any circumstances strong enough to make planar deformational features.

As it turns out, the “shock features” that Jason found are not shock features or indicators of impact at all, at least not according to the experts. ui.adsabs.harvard.edu/abs/2015E%26PS…

So with that background, let’s look at #TEHburst Fig. 28. The caption reads “Shocked quartz from known airbursts. (a) SEM image of 140-µm-wide shocked quartz grain from Tunguska airburst.” But does not attribute the source.

Who collected the sample? Where, exactly, did it come from in the Tunguska airburst area? Who sponsored and led the expedition to collect it? Was it float or from an outcrop? Who prepared it in the lab? And what is the basis for classifying this as shocked quartz?

Regardless of the answers to those questions, 1) The blast pressures at Tunguska were not high enough to generate shocked quartz, 2) Jason’s paper didn’t attribute shocked quartz to an airburst. 3) This is not what shocked quartz looks like.

Here’s what shocked quartz looks like. This is a grain of quartz sand from a shock recovery experiment I did at Sandia Labs using high explosives in the 1980s. Air-coupled shock waves from asteroid explosions are not even close to being strong enough to do this.

When I was hired straight out of grad school, one of my first jobs was to teach a course on shock physics to engineers who were designing explosive components. I'd designed hypervelocity impact experiments as a PhD student. There's a concept called "shock impedance".

You simply cannot drive a strong enough shock from low-impedance air into high-impedance rock from an asteroid airburst. Stand-off nuclear explosions are another story. It's different physics. I wrote my course notes up as a book chapter. See books.google.com/books?hl=en&lr…

Here’s what shocked quartz from an impact crater looks like. I’ve got enough experience with shocked quartz to see the difference between this and the #TEHburst Tunguska sample, but my position on the Dunning Kruger spectrum tells me to defer to the experts. They agree with me.

At the bottom of the #TEHburst (p 63) is the following note: "Correspondence and requests for materials should be addressed to A.W." That’s Allen West, who’s in charge of correspondence & samples for nearly all this group’s research.

Unfortunately, I’ve been blacklisted and have not been able to get samples from this group for over a decade. Here’s Allen Wests response to my request for samples in Sept. 2010:

“I have talked over your request with the others. First, we have very limited samples left.."

"..Second, we prefer to provide what we have to several unbiased third-party researchers first. Given your consistent and strong negative opinions about our hypothesis, the consensus of the group is that we need to wait for the time being.”

But my subsequent requests for samples have also been denied. I don’t think it’s unreasonable to expect samples to be shared with scientists who may be skeptical of a hypothesis. Maybe another skeptic will have more luck this time around.

Some #TEHburst enthusiasts have asked “have you read the paper?” The answer is, I’ve read enough. As my friend David Morrison once said, “Pseudoscience is like spoiled food; you don't have to eat it all to know something is badly wrong. Just a few bites will do."

To be continued.

Correction: 35 degrees. 18 km above surface.

Here's the link to the next thread:

https://twitter.com/MarkBoslough/status/1441041953932537863?s=20