But I don't see anywhere in his blog post where he answers some of the fundamental questions raised by other actual published scientists aside from the "coal ash" argument.
Just to clarify, it seems like the coal ash argument is addressed, but not really answered. As
@FatPhil noted in post #122 above, Loeb says somebody claimed some of his spherules, particularly the anomalous ones, were coal ash (link to Loeb's blog at bottom as it creates a big header):
External Quote:
Lately, some of these commentators promoted the claim that
the spherules we collected in an expedition to the Pacific Ocean and analyzed carefully with the best instruments in the world over the past five months, are coal ash.
I guess reading the exact wording above and giving Loeb the benefit of the doubt, he could be referring to people that may have read the Gallardo paper,
Anthropogenic Coal Ash as a Contaminant in a Micro-meteoritic Underwater Search and were blogging about it.
But the next line in Loeb's blog seems to indicate he's aware of the paper:
External Quote:
This claim is based on unrefereed comments that superficially examined a few elements out of the dozens we analyzed. To be scientifically credible, any such claim must reproduce the measured abundances of all elements and, in particular, demonstrate the loss of volatile elements — as derived in our paper
Meaning he likely knows the actual claim is that the possibility a few of his spherules could have been coal ash and contaminated his sample and that should have been considered and wasn't. His equally unrefereed response to the unattributed claim that his anomalous spherules were coal ash was:
External Quote:
Our team member, Dr. Jim Lem, head of the Department of Mining Engineering at the University of Technology in Papua New Guinea, noted: "The region where the expedition was carried, should have no coal mineralization. In addition, coal is non-magnetic and cannot be picked up by the magnetic sled that was used." Indeed, our "BeLaU"-type spherules have a much higher iron abundance than coal ash. Case closed
I suppose its case closed if he's responding to a random blogger, but Dr. Lem merely asserts the area of the search "should have no coal mineralization". Not that it does NOT have coal or that they tested it for coal.
Even if Lem's assertion were correct, the source of the coal ash contamination need not be naturally occurring coal mineralization in the search area. The title includes the word Anthropogenic:
External Quote:
an·thro·po·gen·ic:
of, relating to, or resulting from the influence of human beings on nature
https://www.merriam-webster.com/dictionary/anthropogenic
The coal ash could be from man-made pollutants from steam engines as noted in the paper:
External Quote:
Multiple reports during the past century have discussed anthropogenic contaminants in samples containing magnetic spherules from microns to millimeter scales in size (Handy & Davidson
1953; Oldfield et al.
1978; Goldberg et al.
1981; Deuser et al.
1983; Locke & Bertine
1986; Wik & Renberg
1991). Most notably, in 1976, another naval expedition in the Gulf of Mexico found large numbers of magnetic spherules from anthropogenic sources in seawater (Doyle et al.
1976). Chemical composition analyses revealed consistency with coal fly ash, a waste product of the combustion of coal in power plants and steam engines.
https://iopscience.iop.org/article/10.3847/2515-5172/ad03f9
Gallardo then compares the values for Be La U and Fe found in the literature with those of Loeb's supposedly anomalous spherules. I've edited a bit here for brevity. L23 refers to Loeb's paper and samples if I'm reading this right:
External Quote:
The abundance reported in Table 1 in Doyle et al. (
1976) has a mean value of 68%, while the iron abundance in the BeLaU sample has a mean of 51%. In consistency with Hock & Lichtman (
1983).
Nickel content has been pointed out as a discriminator between coal ash and meteoritic material (Handy & Davidson
1953). Table 1 in Doyle et al. (
1976) found nickel concentrations of order 0.04% in fly ash. The nickel concentrations in
L23 are of order 200 ppm (0.02%) or lower. Which puts the nickel content in the same order of magnitude of Doyle et al. (
1976).
Nickel content is in consistency with ash from coal.
Figure
1 shows in green the concentrations for the five BeLaU samples, with the expected histogram (in black) of the concentrations from coal ash for beryllium, lanthanum and uranium. COALQUAL data shows that all samples are in the expected range, in consistency with coal ash, and with: Headlee & Hunter (
1953), and Zielinski & Finkelman (
1997).
Note also the amount of iron in coal ash, meaning it could in fact be picked up with a magnetic sled, contrary to Loeb's assertions. In fact, Gallardo argues that while coal ash has a typicaly lower iron content, using a magnetic sled in fact selects for spherules of coal ash with a higher iron content:
External Quote:
The iron content of coal ash has been documented in the context of coal quality control and commercial iron sourcing. Although typical values for the iron content in coal ash range 20%, with a variance of several tens of percent (Myers et al.
1973), higher values can be obtained if the ash is magnetically selected (Murtha & Burnet
1978).
https://iopscience.iop.org/article/10.3847/2515-5172/ad03f9
Lastly, as mentioned before me and math are not friends, but I did try my hand a few calculations. From Loeb:
External Quote:
Our research teams at the Bruker Corporation in Germany and at Harvard University in the US are currently analyzing the remaining 93% of our full sample of nearly 800 spherules.
I'm not sure if "nearly 800" is 750 or 795 but I'm just going with 800. Now 93% of 800 is 744 meaning they have analyzed ~56 samples of which it appears 5 were anomalous:
External Quote:
A three-order of magnitude difference from CI-chondrites has been identified for elements beryllium, lanthanum and uranium in five samples.
https://iopscience.iop.org/article/10.3847/2515-5172/ad03f9
So, at this point around 10% of the samples so far studied are anomalous. I have no idea what percentage of spherules magnetically obtained form random seafloor drags would include spherules of coal ash with a high level of iron, but it seems it should be ruled out before claiming interstellar origins.
Source: https://avi-loeb.medium.com/new-knowledge-must-be-learned-not-preached-ffb287585377