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Playing Error Guitar

Donate Skeptoid corrects another round of errors in previous episodes caught by you amazing listeners.  

by Brian Dunning

Filed under Feedback & Questions

Skeptoid Podcast #694
September 24, 2019
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Playing Error Guitar

Once again we turn to the mailbag and find out where clever listeners have found errors in certain Skeptoid episodes. One great thing about having an audience that consists largely of academics is that errors don't have very good life expectancy; they get picked out pretty quick. So today I'm going to present the latest round of errors found by you good listeners — and correct them — on episodes about the red rains of India, who decides the names of chemicals, the Virgin of Guadalupe, griffins, Nostradamus, global warming, and mercury in fish and the Minimata incident. We'll get started first with a statement falsely attributed to Charles Darwin.

Darwin and the Red Rain

Episode #224 was about red rainfalls in India, often reported in the popular press as blood raining from the sky, possibly as some kind of omen or curse. In more recent years, a pair of scientists whose expertise was in unrelated fields successfully persuaded the world press that the rain was dyed red by the presence of alien spores, an explanation which is still the first one trotted out whenever these red rainfalls happen again (and they do continue happening, though it's still very rare). In the episode, I mentioned:

Researchers noted similar red rainfalls in 1818, 1846, 1872, 1880, 1896, and 1950, including one described by Charles Darwin.

Had alien rain been falling since Darwin's day? Well, not so fast. Listener David from Australia noted that the attribution to Darwin is found pretty much everywhere a red rain report appears in the scholarly literature:

This quote is now used to reference the same claim on the Wikipedia entry for Red rain in Kerala.

Your reference to Darwin noting red rain may have come from Bizarre Weather by Joanne O'Sullivan, where she writes "Charles Darwin wrote about a red rain that he experienced while at sea off the Cape Verde Islands." If you read Darwin's account from both The Voyage of the Beagle, and his paper 'An account of the Fine Dust which often falls on Vessels in the Atlantic Ocean', Quarterly Journal of the Geological Society, 2(1-2), January 1846, Darwin never mentions red rain but refers only to the fine airborne dust particles noted by both himself and other mariners off the coast of Africa.

And, as David's was an awesomely comprehensively cited correction, it turns out he is absolutely correct. Darwin said nothing about red rain, though that was obviously the presentation of what he did report on. Darwin's actual quote, published in 1897, merely said:

The dust falls in such quantities as to dirty everything on board, and to hurt people's eyes; vessels even have run ashore, owing to the obscurity of the atmosphere. It has often fallen on ships when more than thousand miles from the coast of Africa, and at points sixteen hundred miles distant in a north and south direction. In some dust which was collected on a vessel three hundred miles from the land, I found particles of stone, above the thousandth of an inch square, mixed with finer matter.

Note the lack of alien spores reported by Darwin. This was atmospheric dust kicked up from desert on the Arabian peninsula. This still explains much muddy red rain in the area; though this is unrelated to what the actual cause of the red rain discussed in the episode was — and if you want to learn what that was, which is pretty wild and crazy, you want to go back and re-listen to episode #224.

International Unions of Purity

Episode #479 was about chemicals, specifically, how the very word itself has come to be almost a swear word. It's often used to trigger chemophobia in people and scare them away from whatever technology, food, or other product is deemed to be terrible. In the episode, we stated that chemical names are determined according to a set of rules defined by the IUPAP, the International Union of Pure and Applied Physics. Listener David wrote in from Scotland:

A minor correction... It is actually overseen by IUPAC - the International Union of Pure and Applied *Chemistry*.

...and he is absolutely right. This was all Kevin Hoover's fault, who guest-hosted this episode for me a few years ago. Dammit Kevin, you ruined the podcast!! ;-)

The Virgin of Guadalupe

Now let's go all the way back to 2010, to episode #201 on the Virgin of Guadalupe, which is the name for an image of the Virgin Mary said to have been miraculously imprinted on a cactus fiber tunic called a tilma. This was at the time when Spanish conquistadors occupied what is today Mexico, and the Catholic Church governed the lives of the Aztecs. Those of the Dominican order favored using the tilma as a recruiting tool to baptize Aztecs, while those of the Franciscan order — knowing it had been painted by an artist and had not been miraculously imprinted — felt this was wrong and did not want it used in such a way. The Dominicans won, as you can probably guess — a decision which resulted in the apparently "holy" image helping to baptize some 8,000,000 Aztecs.

Listener Robert from Nashville wrote:

I would like to point out what I believe to be a (very) minor mistake in episode 201. In it, you refer to Fray Pedro de Gante as a "Franciscan Monk." As a Franciscan missionary, de Gante would have been a Friar, which (in Catholicism) is entirely distinct from a Monk. However, to your credit, the two are often incorrectly used interchangeably. Keep up the good work!

Robert is correct. Throughout the episode, it appears that I used these terms, and also the term priest, interchangeably. However all three are separate things, though friars and monks are often also priests. So I've cleaned the episode up a bit. An authority on Catholicism I am not, regrettably.

Rudenko of the Griffins

A couple minor but important corrections to episode #442 on griffins. We mentioned the Soviet archaeologist Sergei Rudenko, but unfortunately misspelled his name in the transcript (since corrected) and also erroneously said that he was Russian (an error repeated on his Wikipedia page). He was, in fact, of mixed Ukrainian and Russia heritage. Since he was born in 1940 when both were united as parts of the Soviet Union, we've decided to avoid trying to nail him down more specifically and described him as Soviet. Apologies to any from the region who may have taken offense, and thanks to listener Vladimir for the correction.


Now we'll shift to that perennial favorite, Nostradamus. Woo about history's most famous alleged seer will permeate pop culture forever, it seems. In episode #66 we gave a list of things Nostradamus was known for, followed by a paragraph striking each of these claims down one-by-one. One of these was that his prophecies were placed on the Vatican's list of banned books in the year 1781, which I rebutted with the popularly-repeated assertion that the Vatican had no such list in 1781. Listener Adelaide wrote in:

You mention in your Nostradamus episode that he was "not placed on the Vatican's Index of Forbidden Books in 1781, because the Vatican had no such list in 1781, and he was never placed on any such list in any year." I have no reason to doubt the second part, but there absolutely was an Index of Forbidden Books from the time of the Council of Trent well into the 20th century.

True. There were indeed many editions of this list beginning in about 1559 when the most official such list was published by Pope Paul IV, eventually becoming the Index Librorum Prohibitorum. However its contents are widely available online, and nothing by Michel de Nostredame, nor any other variation of his name, ever appeared on any of them.

Global Warming and Methane

Next is probably the most important screw-up that I made in this batch of episodes, and it came in episode #671 about the relationship between ocean plastics and China's ban on importing recycled raw materials. At one point the discussion turned to landfill emissions, and I said in the show:

Methane is the single most important greenhouse gas to control right now, as carbon dioxide has already saturated its part of the electromagnetic spectrum in the atmosphere.

NO!!! Wrong, wrong, wrong. It is indeed very important to control methane, but the reason has nothing to do with carbon dioxide having already reached some "saturation point". In fact, this is a common talking point of global warming deniers: they say we've already added enough carbon dioxide to that atmosphere to fully realize the amount of heat that it insulates in, so there's no harm in adding more and more by burning more fossil fuels. This is completely false, and it completely misstates the way the greenhouse effect works.

It is not "more important" to control methane than carbon dioxide. We need to control them both. Methane is about 30 times as potent at trapping heat in the atmosphere than carbon dioxide, and as the Earth warms, more and more methane gets released from decaying organic matter. But it's present at far lower concentrations than carbon dioxide, which is really the big one defining the overall shape of the Earth's radiative spectrum.

Thanks to listener Tim for being the first to point out my error and sending me into a mad scramble not only to fix it, but to figure out how I got it so wrong. I should have known better.

Mercury in Fish and Minimata

In a recent Student Questions episode, a student asked about mercury levels in fish, and need we worry about getting mercury poisoning? In the episode, I said:

To date there has never been a known or published case of mercury poisoning in a human from eating fish.

What I meant was commercially caught and sold fish. Many, many people wrote in quickly to say that I forgot about the Minimata incident. This was a case in Japan that lasted several decades which involved principally shellfish living in the mud right at the outlet from a chemical factory that dumped methylmercury-laden wastewater from 1932 to 1968. Local people harvested these shellfish for their own consumption and many developed severe mercury poisoning, but it took decades for the connection to be established. Another smaller but similar case was discovered in Niigata prefecture as a result. The mercury accumulated in the mud with much greater density than it ever could have in the open water, which is why shellfish were a much more deadly vector than fish would have been. However, also as a result of the Minimata incident, three cases were discovered in Ontario involving fish in rivers on First Nation communities similarly affected by severe localized industrial mercury dumping. In all of these cases, the contamination was so severe that it was possible to process the mud in Japan and the river water in Ontario to recover useful amounts of industrial mercury.

These cases cannot be compared to the original question about fish caught in the wild or in the ocean though, as these locations were geographically constricted and did not have any natural dilution. So although it would not be possible for these conditions to exist in areas of commercial fisheries, it was still wrong for me to say there's never been a case of mercury poisoning in a human from eating fish. However it is still true that nobody has ever caught mercury poisoning from commercially available fish, and so far as I could find, no commercial fish catches have ever been found to contain levels of mercury that approached maximum safe levels. So the conclusion still remains: you may continue eating both commercially bought fish and shellfish without concern for mercury toxicity.

Send more corrections!

So keep those corrections coming in. Also, since the last error corrections episode, I've put up a new page at where errors can be reported. Much of this page consists of instructions, because the vast majority of correction emails I receive are from people who have a hunch but no data, or from wooists who believe aliens and poltergeists are actively impacting their life so I should retract about half the episodes. If you have a valid corrections, the information on should give you everything you need to properly report it in a way that passes editorial muster here in the Skeptoid offices. So I look forward to seeing it, and look forward to keeping the bar for good information as high as we can.

By Brian Dunning

Please contact us with any corrections or feedback.


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Cite this article:
Dunning, B. "Playing Error Guitar." Skeptoid Podcast. Skeptoid Media, 24 Sep 2019. Web. 26 Sep 2020. <>


References & Further Reading

Darwin, C. "An account of the Fine Dust which often falls on Vessels in the Atlantic Ocean." Quarterly Journal of the Geological Society. 1 Feb. 1846, Number 2: 26-30.

Harada, M., Fujino, T., Akagi, T., Nishigaki, S. "Epidemiological and clinical study and historical background of mercury pollution on Indian Reservations in Northwestern Ontario, Canada." Bulletin of the Institute of Constitutional Medicine. 1 Jan. 1976, Number 26: 169-184.

Lenard, M. "On the Origin, Development and Demise of the Index Librorum Prohibitorum." Journal of Access Services. 17 Oct. 2008, Volume 3, Issue 4: 51-63.

Nuccitelli, D. "Is the CO2 effect saturated?" Skeptical Science. John Cook, 16 Aug. 2013. Web. 13 Sep. 2019. < >

Scalia, E. "What Is the Difference Between a Friar, a Monk and a Priest?" Aleteia. Aleteia SAS, 7 Dec. 2015. Web. 13 Sep. 2019. <>

Yvon-Durocher, G., Allen, A., Bastviken, D., Conrad, R., Gudasz, C., St. Pierre, A., Thankh-Duc, N., Del Giorgio, P. "Methane fluxes show consistent temperature dependence across microbial to ecosystem scales." Nature. 27 Mar. 2014, Volume 507, Number 7493: 488-491.


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