ESP might meet that description, but as Langmuir said, “a flying saucer is not exactly science,” or, as we might put it, is pseudoscience.
By citing Langmuir to discredit the YDIH, the Requiem authors tacitly label it “pathological science.”
Gratzer’s book, “The Undergrowth of Science: Delusion, Self-Deception, and Human Frailty,” covers such failed ideas as cold fusion, eugenics, the “Jewish Physics” of the Nazis, memory transfer, polywater, and more, a sad but instructive list. It ends with this statement:
Scientists, for all their vaunted training in observation and skepticism, are as much a prey to human frailty as anyone else, and their capacity for unbending objectivity is circumscribed. Even skepticism has its dark side. Schopenhauer wrote that all truth passes through three stages: first it is ridiculed, then violently opposed and finally accepted as self-evident. Charles Kettering, the mogul of General Motors, enlarged on this enduring article of human nature: “First they tell you you’re wrong and they can prove it; then they tell you you’re right but it isn’t important; then they tell you it’s important but they knew it all along.
Robert Park’s “Voodoo Science: The Road from Foolishness to Fraud,” deals with perpetual energy, cold fusion, the Roswell UFO, Homeopathy, Deepak Chopra, animal magnetism, and on through another depressing list.
Park’s well written book ends with a poignant lesson that, like Gratzer’s statement above, scientists on each side of a dispute should bear in mind:
Most of the scientists and inventors we met started out believing they had made a great discovery. Like all those who have gone down this road before them, they will have reached a fork. In one direction lies the admission that they may have been mistaken. The more publicly and forcefully they have pressed their claim, the more difficult it will be to take that road. In the other direction is denial.
Some will start down the road of denial but recognize in time that they are headed in the wrong direction and turn back. A surprising number — apparently unable to face turning back, and yet unwilling to follow the road all the way to fraud — seem to leave the road entirely, completely losing touch with reality.
Thus the lesson that the Requiem authors wish us to take from the three examples is not just that the YDIH is wrong, an honest mistake if you will. Rather they are implying that the hypothesis is nothing more than pathological pseudoscience, no better than cold fusion, UFOs, eugenics, perpetual motion, and the like. To read such an accusation in a peer-reviewed article is shocking. Why was it necessary to go that far?
To return to Park’s point, those who oppose a hypothesis from the outset, before significant negative evidence has come to light, or who accept such evidence without careful scrutiny, or who reject a hypothesis because it violates orthodoxy, they too travel down Park’s road to come to a fork. If they choose the road of continuing opposition even as the positive evidence mounts, the other fork, the path to acceptance, is effectively closed to them, for scientists who oppose a theory in print rarely change their minds.
The combination of the GSA Today article, Surovell et al., and The Requiem planted the belief in the minds of scientists at large that not only had the YDIH had been falsified, its proponents may have committed scientific malpractice. No one ever came right out and made that accusation, but if the event-marker peaks do not exist, how else could anyone have claimed they did?
PART II:
EVIDENCE FOR AN EXTRATERRESTRIAL EVENT
To this point, we have proceeded in more or less chronological order from the first glimmerings of the YDIH in Mammoth Trumpet to its early death, funeral, and Requiem. To continue in this fashion as the number of articles rose would quickly become overly complicated. Instead, in PART II, I will organize by type of evidence.
7
SYNCHRONY
A few years after the Alvarez Theory appeared in 1980, Charles Officer and Charles Drake, Dartmouth professors who became the theory’s most obstinate opponents, published two critical articles in Science that argued that the transition from the Cretaceous to the Tertiary had first, not been instantaneous but had stretched over tens of thousands of years, and second, had taken place at different times at different places. If both were true, the Alvarez Theory would have been falsified in one fell swoop with no need to appeal to any other evidence.
But as age measurements became more precise, both claims failed. Not only was the KTB found to be the same age everywhere, both the impact and the mass extinction dated exactly to that age.
We know from the temperature record as derived from oxygen isotope ratios that the onset of the YDB was sudden, so the first claim above did not apply. But the second might, and if the boundary were found to have different ages at different YD sites, then it could not have resulted from a single instantaneous event. Thus, dating the YDB became crucial to the evaluation of the impact hypothesis.
AMPLIFIED CONCERNS
At first, radiocarbon dating seemed a scientist’s dream come true. Prior to Willard Libby’s invention of the method, there was no way to measure ages as young as a few thousand years. It is no exaggeration to say that radiocarbon dating revolutionized archeology, anthropology, Pleistocene geology, and more. But as with any new method, no sooner had scientists begun to use it than problems appeared. They first tested the method against objects whose age is known from history, such as artifacts from ancient Egypt, and initially got reasonable agreement. But the more objects they dated, the more discrepancies they found. As noted earlier, it soon became clear that the proportion of radiocarbon in the atmosphere is not constant, so that one cannot simply measure the proportion today and assume it applies in the past. Scientists got around this otherwise fatal flaw by using tree rings to calibrate the method, but many other potential error sources cropped up. C-14 was found to vary over time due to carbon turnover in the deep oceans, fluctuations in Earth’s magnetic field, the release of C-14 from wildfires, the influx of C-14 from long-period comets, variations in cosmic ray intensity, and so on. Radiocarbon dating is a tricky business, but with enough care, enough data, and today, the use of proper statistical methods, it can prove reliable.
In 2014, four anthropologists published: “Chronological Evidence Fails to Support Claim of an Isochronous Widespread Layer of Cosmic Impact Indicators Dated to 12,800 Years Ago.” They reviewed previously reported radiocarbon dates from 29 YDB sites to determine whether their ages were identical and correspond to the age of the boundary as identified by the proponents of the YDIH: ~12,800 calendar years ago. If not, the YDIH would have been falsified, or at least struck a heavy blow. And indeed, the article reported that only 3 of the 29 dates passed the test, and the quality of those 3 measurements was questionable. “For now,” they concluded, “there is no reason or evidence to accept the claim of an extraterrestrial impact at the start or as a cause of the Younger Dryas,” thus dismissing all the evidence that had come to light prior to 2014.
The article focused on 11 well-known YDB sites including Abu Hureyra, Syria; Blackwater Draw, Murray Springs, and Topper, yet found that 9 of them “have predicted ages for the supposed YDB that fall outside the YD onset time span.”
The authors adopted a reasonable age for the YDB, then checked to see whether the reported ages from YD sites matched that age, which they did not. But they also noted the imprecision inherent in radiocarbon dates: “No single value can completely describe the probability distribution of a calibrated date, and therefore, using just a single point estimate — whether a median, midpoint, or weighted mean — fails to account for uncertainties in the age estimate and thus leads to questionable regression results.” However, that did not cause them to temper their conclusions.
BAYESIAN ANALYSIS
By the time the four wrote, radiocarbon specialists, recognizing the inherent imprecision in a single radiocarbon date, had begun to use a new statistical method called Bayesian analysis.
Scientists typically measure a number of radiocarbon dates at a single si
te and correct them using the latest calibration curve. To assess and compare the many dates that result, each with its own precision, they must use models and statistical techniques. In the process, they have discovered that calibrated radiocarbon dates do not conform to the bell-curve of a normal distribution, so that many standard statistical methods do not apply. Instead, the radiocarbon specialists turn to Bayesian statistical analysis, in which the quality or “degree of belief” in a data point is used as well as the actual date obtained from the measurement. Bayesian statistics has become state of the art in radiocarbon dating.
In a 2015 paper in PNAS, James Kennett and 25 others reported the results of the use of Bayesian statistics on radiocarbon dates from the YDB on four continents. Their analysis used 30 existing age determinations, 23 from known YDB sites and 7 from independent dating of the YD, such as from ice cores, ancient lake beds, and cave deposits. Within the limits of resolution of the Bayesian method (± 100 years), the 23 YDB sites have the same age: 12,835–12,735 years ago. They also re-examined the nine sites described in the article above, ones whose ages had been found to lie outside the YDB range. Each now fell within that age range. As we will see in Chapter 12, since the publication of the Kennett et al. paper a number of new or newly investigated YDB sites have been dated. In each case, their age also falls within the Kennett et al. range.
To sum up: YDB sites occur on several continents and in several different geological settings. At each, the YDB layer has the same age within the resolution of the Bayesian method. This fact corroborates the conclusion that the YDB layer reflects a process in which micro-objects settled from the air. As we have noted, the two possibilities are volcanic eruptions and extraterrestrial events, either of which could have thrown up a cloud of particles that reached the stratosphere and spread at least on a continental scale. But as we will see later, the most promising volcanic candidate, the Laacher See eruption in Germany, fails because it is just slightly older than the YD. Thus by elimination, the results of Bayesian radiocarbon dating analysis do more than merely avoid falsifying the YDIH, they strongly corroborate it. One might go farther and say the synchronous ages defy any other explanation. They more than satisfy our Prediction 1: The YDB will have the same age everywhere
But still, the crux of the YDIH remained the microspherules, widely regarded as irreproducible on the basis of the SEA article. If that were true, scientists would never accept the hypothesis no matter the synchronous YDB ages or any other evidence. The microspherules were key.
8
MICROSPHERULES
CONFLICTING RESULTS
In Chapter 5, we raised the question of whether it was sound scientific practice to allow the absence of evidence that SEA reported to outweigh the positive evidence presented by FEA. We did not try to identify where SEA might have failed to find microspherules due to some flaw in their methodology. But such a criticism did not take long to arrive.
In a 2012 paper, LeCompte et al. described a “blind test” in which they collected microspherule samples from three YDB sites, packaged them according to site and scrambled the packages so that the subsequent investigator would know only the site from which a sample came and not its depth in relation to the YDB. The samples “were distributed by a non-participating third party for blind processing.” Senior author Malcolm LeCompte then analyzed the microspherules in the randomly ordered samples, without knowing from which site and what depth they came from.
At sites where SEA found no microspherules, LeCompte et al. found hundreds. They showed that it was SEA’s results that were irreproducible, not those of the original PNAS paper. At Blackwater Draw, on which we focused earlier, LeCompte et al. found not only abundant microspherules, but a substantial peak.
LeCompte and colleagues pointed out the errors in SEA’s methodology, finding that they “deviated substantially” from the FEA procedures:
• Sample sizes too small to be statistically significant.
• Grains not properly sorted by size.
• Microspherules rejected because they were not nearly perfect spheres.
• SEM imaging and geochemical analyses [XRS] not done, making it impossible to distinguish those microspherules that resulted from a cosmic impact event.
The last error is critical. Microspherules that appear similar derive from several different sources, both terrestrial and extraterrestrial. These include particles ablated from incoming meteorites, “fly ash” from coal furnaces, ejecta from volcanic eruptions, and terrestrial target rocks melted at high temperature in an impact or airburst and ejected. To distinguish these different types requires more than looking at their surfaces with an optical microscope, which is as far as SEA went. Positive identification of impact-related spherules also requires analysis by SEM to inspect their surfaces for the characteristic micro-textures diagnostic of impact. X-ray spectrometry (XRS) must be used to establish their chemical composition. In the discussion of methods in FEA’s Supplemental Information, they clearly stated that these techniques had been part of their analysis: “These spherules were either left whole or sectioned and given a microprobe polish for analysis by laser ablation or x-ray fluorescence (SEM/XRF).” FEA included photographs taken by SEM, making it even more plain that they used the technique and thus gone far beyond the range of the optical microscope.
At three points in their article, SEA gave assurance that they had followed the procedures of FEA:
Using methods from the original Firestone et al. study, we examined concentrations of magnetic minerals and microspherules from sediment columns spanning the Younger Dryas boundary.
In both the resampled sites and our additional sites, using methods taken from Firestone et al., we failed to reproduce their results.
Our methods followed those of the original Firestone et al. study.
But they did not use SEM and XRS, necessary for a positive identification of ET microspherules. Why they did not do so is not known. But if one had to summarize in one sentence the paramount reason for the premature rejection of the YDIH, this is it.
As replication of the findings of LeCompte et al., in 2016 another group published a detailed study of the YD section at Blackwater Draw. Using SEM and XRS, as well as other analytical techniques, they found ET microspherules with melted, dendritic surfaces that peaked at a thin layer just at the YDB. They suggested that “SEA just failed to sample the microspherule-rich layer [at Blackwater Draw] because it is visually featureless and very difficult to identify in the field.” If so, SEA would not have found abundance peaks even had their procedures been impeccable.
ONE-THIRD OF THE PLANET
At about the same time as LeCompte et al. published, Bunch et al. reported on their study of microspherules at 18 YDB sites in North America, Europe, and Asia, “spanning 12,000 km around nearly one-third of the planet.” They used SEM and X-ray spectrometry and found abundant ET microspherules at the YDB but none or few above it. At three of the sites (Abu Hureyra, Syria; Melrose, Pennsylvania; and Blackville, South Carolina) they found “scoria-like objects (SLOs),” silica-rich glass with sponge-like holes that matched the spherules geochemically and appeared to have been melted and quenched, as would have happened in an ET event. These SLOs, which others would call “meltglass,” turn out to be important and we will return to them.
At some sites, Bunch et al. found a rare form of silica called lechatelierite, previously known only from impact sites, nuclear tests, and lightning strikes. Lab experiments show that lechatelierite requires shock pressures of over 800,000 atmospheres and temperatures above 2,000°C (3,600°F). Bunch and colleagues showed that the YDB lechatelierite was not caused by lightning, leaving cosmic impact as the most plausible origin.
They compared the compositions of the YDB microspherules with known manmade spherules and with fly ash collected from 48 sites in 28 countries on five continents, considering five possible origins:
1. Human activities: Power plants, smelters, and wildfires produce microspherules. B
ut 75% of the YDB microspherules and SLOs have compositions different from such anthropogenic spherules. Furthermore, they occur buried 2–14 meters below the surface, out of the reach of modern terrestrial processes.
2. Volcanic eruptions: 85% of the YDB microspherules have compositions unlike those of volcanic materials. They also lack typical associated volcanic markers such as volcanic ash and tephra.
3. Authigenic (formed naturally within the rock in which they are found): The microspherules have a different chemistry and features from expected authigenic materials, which show no evidence of melting.
4. Melted fragments ablated from asteroids or comets: More than 90% of the microspherules are geochemically distinct from cosmic material.
5. Impact-melted source rocks, aka the “country rock” at the different YDB sites: The chemical composition of the microspherules resembles that of known impact-derived materials such as impact spherules, impact ejecta, and tektites, as well as melted sediments from aerial nuclear blasts. Their chemistry is consistent with their derivation from impact-melted, common surficial rocks.
Thus, based on their chemistry and features, rather than on their abundance and peaks alone, the microspherules corroborate the YDIH. This satisfies our Prediction 2: The composition and features of the event markers will allow them to be distinguished as extraterrestrial rather than terrestrial.
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