Hunches

The 1052 white vapour matches the 1052 radiocarbon candidate

Same year, a northern glow at a mid-latitude site, and a small unconfirmed solar particle event. No published paper connects them as of 24 October 2026. The carbon-14 side after one day of checking: six annual tree-ring series cover these years. Three (English oak STK-C10, a California full-ring sequoia, the Kujawy oak in Poland) have their first high ring at 1053, exactly what a December 1052 event should produce. Three (Furness Abbey oak, two other California sequoia series, a Finnish pine) have it at 1055, which fits the 1054 supernova instead. Two of the disagreeing series are sequoias from the same mountains, so the split is probably laboratory and ring-dating offsets, not two events. The timing test is a draw until someone measures several trees in one lab. The record side: Korea logged a turtle-shaped white vapour in July 1052 but nothing in winter. Japan has no catalogued aurora 1033 to 1071. The Annals of Ulster, the British phenomena list and the Anatolian catalogue have nothing for the winter of 1052 to 1053. Ireland has a tower of fire in April 1054, usually called a tornado. Fritz 1873 has no European aurora from 1031 to 1069. Hermann of Reichenau and the Islamic chronicles are still unread. Still not a finding: one winter record, the weakest aurora class, and a carbon-14 step that one of two English oaks does not show. Why this record matters more than it looks: the Song history has only one aurora candidate in the entire 1050s decade, and it is this one. The East Asian catalogue has nothing between 1033 and 1067 except Korea in July 1052. Compare the 1260s, when glows were logged most years. A lone glow in an empty stretch is a much less likely coincidence than a glow in a busy one. Added 25 October 2026 from Miyahara et al. 2022: oaks build spring wood from the previous year's stored sugar, so oak radiocarbon can lag conifers by a year. Two of our three '1053' series are oaks, so they fit an event in 1052 but cannot pin it to December. The conifer series still split: Eastoe's sequoia rises into 1053, Terrasi's sequoia and pine into 1054 to 1055. The timing test stays a draw. New alternative, 25 October 2026: the Goryeosa records a comet in the southern sky on about 25 February 1053 with a tail over 1 zhang. If that comet was in the northern evening sky in mid December 1052, its tail could be the Chinese 'white vapour in the north'. Worth asking Dr Hayakawa, who will know the Chinese comet records for that winter. Korea's lunar eclipse of 9 December 1052 matches the Moon phase in the Chinese record four days later, a good check that the dates line up.

• Hermann of Reichenau, chronicle entries 1052 to 1054
• Wang et al. 2021 Korean catalogue (2,013 records) for winter 1052 to 1053
• Ask Hayakawa's group how they rate the 13 December 1052 record and whether anyone has tied it to the radiocarbon candidate
• Watch for a multi-tree, single-lab study of 1050 to 1058

Korea's violet glow of 25 October 1279 falls in the window for the 1279 to 1280 radiocarbon jump, and the main paper missed it

Miyahara et al. 2022 confirmed a radiocarbon jump between the 1279 and 1280 rings of their conifer (from -12.36 to -9.16 permil) and wrote: 'No auroral activity has been found around 1279 to 1280 CE.' By their own timing rule, the burst must have arrived between about August 1279 and mid 1280. The Yau, Stephenson and Willis catalogue (1995, entry 291) has a Goryeosa record for 25 October 1279: 'A violet vapour was seen in the west. It was more than 10 chi long. Its light was similar to that of lightning.' We checked the day name: gui-hai falls on 25 October 1279. That is inside the window. Why it is not yet a finding: one record; violet and western is unusual for an aurora seen from Korea, and 'like lightning' could mean a distant storm. The radiocarbon jump is real in Miyahara's data but smaller or absent in two oak series. Still, this meets our rule for 'looking good': a dated record in the right window, matching a confirmed radiocarbon event, and not in the paper that confirmed it. Checked in the original text (Goryeosa volume 53): '五年九月癸亥，紫氣見于西方，長十餘尺，光如電'. It is filed among the red omens, while thunder and lightning on nearby days are filed separately as weather, which suggests the court astronomers saw it as a glow rather than a storm. The day falls on 25 October 1279 once the leap month of 1278 is counted. It is also absent from Wang et al. 2021 by design, because that catalogue only lists red glows. Japan checked 25 October 2026: the Japanese court diaries in the Kokiroku database have no red or white vapour in 1277 to 1282, so Korea's glow remains a single witness.

• Ask Dr Miyahara whether they considered the 25 October 1279 Goryeosa record (added to the email draft)
• Read the original Goryeosa wording for 1279 and its astronomical-treatise context
• Check Wang et al. 2021 for any other Korean entries between August 1279 and mid 1280

Strasbourg 1518 came after a great drought and two years of dear bread

Tested 25 October 2026. Weather: the summer of 1516 was dry, and March to June 1517 is tied for the 3rd driest spring in 400 years of written records (only 1540 and 1893 drier); tree rings put 1517 among the 4 driest years at Strasbourg in 900. Prices: rye in Strasbourg cost about double the normal in 1516 and 1.4 times normal in 1517 (wheat 1.7 and 1.6). Correction to our first reading: by 1518 grain was back to normal or cheap (wheat 0.75 of normal), and July and August 1517 were wet, so the 1517 harvest was probably not a failure. The dancing in July 1518 came about a year after the worst of the hunger, not at its peak. That still fits a stress explanation (people worn down by two hard years, and the disease that often follows famine) but it is not a simple 'hungry month' trigger. Across the other dances there is no price signal, so hunger is not a general rule for them. I found no paper that ties the 1518 dancing to the 1516 to 1517 drought. Still to check: the daily weather diaries of Johannes Indagines (Rheingau, 1517 to 1519) and Johannes Stoeffler (Tubingen). Diaries parked 25 October 2026: tambora.org was unreachable (for us and for Ken), and the Euro-Climhist database (echdb.unibe.ch, University of Bern) needs a free account. The daily diaries of Kilian Leib (Rebdorf, 1513 to 1531), Johannes Stoeffler (Tuebingen, 1507 to 1530) and Johannes Indagines (Rheingau, 1517 to 1519) would only add detail; the drought already rests on two independent sources.

KTU 1.78 records the total eclipse of 5 March 1223 BC

Checked 25 October 2026. 1223 BC is the only total eclipse of the period with Mars beside the Sun, which explains the choice. But Ugarit's chance of totality is only about 5 to 11 percent unless Earth's rotation correction is set about 2 sigma high, and the 1989 paper set it from this very eclipse, so date and correction are partly circular. Not ruled out, but it should not be used as a fixed anchor for Ugarit's chronology or for Earth's rotation. The 1192 BC link to Ugarit's fall is no more likely on the astronomy (0.15 to 0.20).

Joshua's 'Sun stand still' was the annular eclipse of 30 October 1207 BC

Checked 25 October 2026. Astronomy: confirmed. The ring of fire crossed Gibeon whatever reasonable Delta T is used, and it is the only near-certain central eclipse there between 1300 and 1132 BC, so the choice is not cherry-picked. Against it: it happened with the Sun only 7 degrees above the horizon just before sunset, which fits 'the sun stood in the midst of heaven' poorly; the midday total eclipse of 1131 BC fits that phrase but had only a 44 percent chance of being total at Gibeon. Whether the story remembers an eclipse at all is a question about the text, not the sky. Our calculation independently reproduces Khalisi 2021, so nothing here is new.

The 1054 supernova, not the Sun, made the carbon-14 rise of 1053 to 1055

A rival to our 1052 hunch. The Crab supernova was first seen on 4 July 1054. If its gamma rays raised carbon-14, the rise should start in the 1054 or 1055 ring, which is what Scifo 2024 and Terrasi 2020 see. If the rise starts in the 1053 ring, which is what Brehm 2021, Eastoe 2019 and Rakowski 2026 see, the supernova came too late and a solar event in late 1052 fits better. Points against this hunch: Dee et al. 2016 looked at tree rings across four historical supernovae and found no carbon-14 rise at any of them, including 1054. Panyushkina et al. 2022 could not attribute the signal to either cause. Standard physics says a supernova 6,500 light years away is far too weak to change carbon-14 measurably.

• Find a published calculation of how much carbon-14 a supernova at 6,500 light years could add
• Get more trees with annual rings across 1050 to 1058 measured in one lab

Kyoto and Augsburg saw the same great aurora on 21 September 1098

Same night and same direction (north) as Augsburg's 'blood-red clouds toward the north', with Europe seeing auroras again on 25 to 27 September. But the Kyoto note gives no colour: 'strange clouds' in the north and two white bands across the sky. White bands are a common East Asian aurora description, yet at Kyoto's latitude a great storm would usually show red, and strange clouds at dusk can be ordinary clouds. So this is an intriguing same-night coincidence, not yet a confirmed aurora. China records nothing (the Song list jumps from 1088 to October 1099). No paper found linking these records. To do: Sigebert of Gembloux and the Angers annals in the original; Goryeosa for September 1098; Kyoto's magnetic latitude in 1098; other Japanese diaries for 承徳2年8月 (e.g. Gonijo Moromichi-ki, which ends 1099). Korea checked 25 October 2026: nothing in the Goryeosa for the 8th month of 1098. With China and Korea silent and no colour in the Kyoto note, this stays a same-night curiosity, leaning weak. Parked.

The 1286 eruption really happened in 1285

A big two-pole sulfur signal, yet a bright, colourful eclipse over England and Italy in October 1287. We first offered two explanations: the eruption came early (1285) so the veil had thinned by October 1287, or the volcano was southern and its veil stayed south. Tested 24 October 2026 with the monthly ice-core data published with Guillet et al. 2023. The southern-veil idea is weakened: Greenland received about as much extra sulfur as Antarctica. The Greenland record lags by over a year, but it does that after other eruptions too, so it is a dating drift, not a clue. The early idea is supported: Antarctic sulfur starts climbing in August 1285 and peaks in September 1286, so the eruption most likely happened in the first half of 1285, about two years before the bright eclipse. That is long enough for a veil to thin, though not certainly long enough to vanish. No eclipse descriptions survive for 1284 to 1286 in the study's European or Japanese datasets, and the East Asian aurora catalogue has nothing from 1280 to 1287 either. So the remaining test is any written record of a dim sun, red twilights or a dark eclipse in 1285.

• Korean and Chinese records of a dim or reddish sun in 1285 (the Goryeosa five-elements treatise, the Yuanshi)
• Total lunar eclipses visible in East Asia: 4 January 1284 and 29 April 1287; look for colour notes
• Ask whether the 1285 timing matches any undated young caldera in the tropics

The 1453 omens were made by the volcano

Checked 25 October 2026. Of the four omens: (1) the strange Moon of 22 May was an ordinary partial eclipse rising at sunset; no volcano needed, and Barbaro says the air was crystal clear. (2) A thunderstorm with hail in early June is ordinary. (3) A fog lasting all day is almost unknown in Istanbul between April and October today (0 in 29 years), so it is the one real oddity, but it rests on Kritovoulos, who was not there and uses it as a Bible-style sign, and Barbaro, who was there, does not mention it; smoke from the siege guns and fires is another possibility. (4) The light on the dome comes from a later Russian tale, and Barbaro records huge Ottoman camp fires on 26 May that would light the city. Verdict so far: most of the omens do not need a volcano; the fog is unexplained.

The second 1458 volcano matches no known eruption: a continental-crust rhyolite, far south, never studied

The 1458 to 1459 sulfur in Antarctic ice carries two kinds of glass: dacite that fits Kuwae in Vanuatu, and rhyolite from an unknown volcano outside the tropics in the southern hemisphere (2025 Vostok study). The proposed source, Reclus in Patagonia, had no recorded eruption then and its glass is a poor match. We compared the rhyolite against every reference glass in the 2025 and 2023 datasets. No volcano is a clear match, but potassium narrows the field: the source was a volcano on continental crust, not an ocean-island arc (rules out the Kermadecs and Tonga) and not an Antarctic volcano. That leaves the southern Andes or New Zealand's Taupo zone. New Zealand's ash record shows no rhyolite eruption after 1314, so the southern Andes are favoured, but not Reclus specifically. Why this fits our project: these icefield volcanoes are remote, and in 1458 the only people nearby were the Kawesqar, Aonikenk (Tehuelche) and Yaghan, whose traditions were written down centuries later, if at all.

• Ask a tephra lab: do trace elements exist for the 1458 shards (Hartman 2019 South Pole core)? Trace elements would separate candidates that major oxides cannot
• Lake and peat cores in southern Patagonia with an ash layer near 490 radiocarbon years: any unanalysed rhyolite?
• Poorly studied Austral volcanoes with few or no glass data: Viedma, Aguilera, Cook Island; check whether any has a young cone

Sweating sickness outbreaks followed slightly wet summers: a weak hint that did not strengthen

The old claim is that outbreaks followed prolonged rain. First test (25 October 2026): the two summers before an outbreak were wetter than normal in England (chance 7 percent) and in northern France (6 percent), about 3 percent combined. Second, fairer test the same day: each of 171 French outbreaks measured at its own department against that place's own climate, with the outbreak pattern slid along the record so clustering cannot fake a signal. The chance stayed at 6 percent, but the effect is tiny: outbreaks followed summers only 0.06 of a typical year-to-year swing wetter than usual. England's five outbreaks: 0.63 of a swing wetter, chance 8 percent; 1517 still contradicts. Verdict: moved back from 'looking good' to 'not checked yet'. A real but very weak lean toward wet years, or noise. It does not single out any cause.

• Seasonal rain records (winter and spring) instead of summer soil wetness, since the chroniclers spoke of wet winters
• Harvest and grain price series for northern France 1718 to 1874 as a second measure of bad wet years

Cocoliztli broke out in wet years in central Mexico

Tested 25 October 2026 (exploratory, not the pre-set test). Drought atlas: epidemic years wetter than normal (all 14, p 0.008; the 4 major, p 0.008); 1576 struck in a wet decade after the 1572-73 drought. Fits a rodent boom after rain, but equally waterborne enteric fever (Salmonella Paratyphi C was found in 1545 victims). Not seen in the Puebla maize record (epidemic years mean -0.07), so it needs a third proxy (for example the Queretaro baldcypress record or written rainfall reports) before trusting it. The 2002 paper already noted that 1545 and 1576 began in rainy years; the tests across all 14 epidemics and the northern-only megadrought look new. Third record (Queretaro bald cypress, 25 October 2026): no year-by-year wet signal (all 14 p 0.40). The year-level result rests on the drought atlas alone, so downgraded to OPEN. What holds across records is the decade-scale picture: the great epidemics struck in the long wet era (1540 to 1580) that followed the worst central-Mexican drought of the last 600 years (1514 to 1539).

The Roanoke drought began in 1586 and also hit Ralph Lane's first colony

Found 25 October 2026. In the many-site atlas the extreme drought runs 1586 to 1588, a year earlier than the usual 1587 to 1589, with the winter-spring of 1586 at 57 percent of normal rain. Ralph Lane's first colony (1585 to 1586) ran short of food, quarrelled with the Secotan over corn, and left with Drake in June 1586. The drought may be part of that story too. To check: whether Lane's or Hariot's accounts mention dry weather, and whether this has already been noted.

Look west of the Americas for December 1808

The eruption was tropical and, judging by silent Spanish colonial archives, not in Latin America. That points to the Pacific, Indonesia, the Philippines, Melanesia or East Africa. A first search on 24 October 2026 found no compiled Asian or Pacific record of a dim sun, red skies or ashfall in December 1808; the published studies used only South American eyewitnesses and British East India Company ship temperatures. The two kinds of glass in the ice (andesite in Antarctica, dacite in the Yukon) might mean two volcanoes, which would widen the search. First Asian check, 25 October 2026: the Joseon Royal Secretariat Diary in Seoul, read day by day for November 1808 to January 1809, records no dim or red Sun and no haze; that winter was clearer than the one before. Weak evidence against a volcano close enough to Korea for its haze to be obvious, but the diary's weather line is too brief to rule out a thin high veil. Bogota and Lima remain the only places known to have noticed.

• Johnson's Fire Mountains of the Islands: any navigator's report of an eruption or ash in 1808 to 1809 in Papua New Guinea, Rabaul or the Solomons
• Fiji sandalwood traders and whalers in the southwest Pacific, late 1808 (the sandalwood rush was at its height then)
• Plunkett 2023 and Hutchison 2023: what the glass chemistry says about the Indonesian candidate
• Wikipedia's suggested zone: tropical, probably southern hemisphere, no further than 20 degrees south, between Indonesia and Tonga

Lunar eclipses could date the 1808 eruption, if someone in the Americas described the November 1808 one

During a total lunar eclipse the Moon is lit only by sunlight bent through Earth's atmosphere, so after a big eruption eclipses go very dark. Correction, 24 October 2026: we first thought nobody had tried this for 1808. Stothers did. He searched more than 300 journals for eclipse colours from 1801 to 1881 and found none usable between 1805 and 1812, writing that reports are 'too sparse in this period to detect this eruption'. The 1812 eclipse he did find was normal, so the veil was gone by then. What we add: Caldas's description of the 9 May 1808 eclipse in Bogota, orange and reddish, a normal Moon seven months before the eruption. Stothers' table has nothing between 1805 and 1812, so this fills a hole in his series. And the decisive eclipse, the total one of 3 November 1808, could be seen only from the Americas and the Pacific, which a mostly European search would miss. Eclipses to use: 10 May 1808 total (Americas, normal per Caldas); 3 November 1808 total (Americas, Pacific); 30 April 1809 partial 87 percent (Europe, Africa, eastern Americas); 23 October 1809 partial 83 percent (Americas, Pacific, East Asia). Searched with no result: the Bogota weekly 1808 to 1809, American Philosophical Society Transactions, American Academy Memoirs, the German astronomy journal 1809 to 1813, and by hand (Ken) Chronicling America, HathiTrust and the Gazeta de Mexico. An expert's search of 300 journals also came up empty, so this needs Spanish-American, Japanese or ship sources, not more European ones.

• Spanish-American observatories and gazettes: Lima (Unanue's Mercurio Peruano circle), Mexico City (Gazeta, Alzate's circle), Havana (Ferrer), Caracas
• Japanese shogunate astronomers for 3 November 1808 at moonrise and 23 October 1809
• Pacific ship logs, night of 2 to 3 November 1808
• Send Caldas's May 1808 description to Guillet's team; their 2025 EGU work extends eclipse ratings to 1600 to 1850

Hobbyist idea: Tambo Quemado in the Bolivian Andes was the 1808 volcano

Proposed in a 2023 VolcanoCafe blog post by Hector Sacristan, which Ken found through Reddit. Tambo Quemado sits at about 18 degrees south on the Bolivia and Chile border, inside the zone the haze reports point to. From satellite maps the author estimates a young tuff cone of about 7 cubic km plus ash, a large eruption that was 'very big but very weak', which could go unnoticed in an empty high desert. For it: right latitude, looks geologically young, close enough for the haze to reach Lima and Bogota within days. Against it: it has never been dated, so it could be thousands of years old. The author guesses its rock is rhyolite, while the glass in the ice is andesite and dacite, a mismatch another blogger pointed out under the post. And Spanish colonial archives are silent; a big eruption 150 km from Arica and near the mining towns of Carangas and Oruro in December 1808 would likely have been reported. Other hobbyist candidates mentioned in the same circles: Putana in Chile (probably too small) and Savo in the Solomon Islands. Why it is worth keeping: it is cheap to test, and one of the tests is our kind of work.

• Colonial records from Arica, Tacna, Oruro and Carangas for December 1808: any ashfall, darkness or noises (our method)
• Search for any radiocarbon or argon date on Tambo Quemado published since 2023
• Compare published Tambo Quemado rock chemistry, if any exists, with the 1809 ice glass

Hobbyist idea: Putana in Chile was one of several eruptions behind the 1809 signal

From the r/Volcanoes post Ken found (August 2023) and a VolcanoCafe comment. The claim is that Putana erupted around 1810 and that its ash fits the glass found in the ice, but that it was too small to make the whole signal, so it was one of a cluster. What checks out: the Smithsonian's volcano database does list a Putana eruption 'about 1810, give or take ten years', with no details. The cluster idea matches the published evidence that the ice layer holds glass from more than one source (Yalcin 2006; Plunkett 2023 points to Antarctic, Alaskan and Indonesian sources). What does not: the same database cites a later assessment that Putana had no historical eruptions at all, and the plus or minus ten years means the date is barely known. The 'ash fits the ice' claim comes from a blog comment, and we found no published chemistry comparing Putana with the 1809 glass. Putana is not among the sources Plunkett 2023 names.

• Find the original report behind the Smithsonian's '1810 plus or minus 10' Putana entry
• Look for any published Putana glass chemistry

Mostly known: the drift fits abandonment on 25 Nov (Richardson 2007); only the storm of 30 Nov to 2 Dec against the 1873 'no heavy weather' argument may be new

Checked 26 October 2026 against Blumberg 2007 (pasted by Ken). MacGregor and Richardson used the same ship-log database (ICOADS) and found the ship could have drifted from Santa Maria to the meeting point with no crew: 'it basically just sailed itself'. They also put the abandonment on the morning of 25 Nov, after rough seas and winds over 35 knots the night before, a likely fouled pump, and a chronometer error of about 120 miles that made landfall three days late. Our drift result (about 5 percent of the observed wind speed, sailing across the wind) independently reproduces theirs: a calibration, not a discovery. What the article does not mention: the force 10-12 north-west storm of 30 Nov to 2 Dec on her route (pressure fall of 27 hPa), which answers the 1873 inquiry's claim that she met no heavy weather and so must have been abandoned later, and fits her blown-out foresail and upper fore-topsail. Small and possibly in the film itself; not worth an email on its own.

Sky-fall myths are no more common near young craters than anywhere else

Tested 25 October 2026 with Berezkin's catalogue of 958 societies (script: scripts/myth_craters.py). For each sky-catastrophe motif we compared societies within 1,000 km of a young impact with all others, shuffling the motif among societies of the same country so that regional habits cannot fake a signal. Results: former sky has fallen 4.7 percent near versus 3.0 percent elsewhere (p 0.12); world destroyed by fire 14.9 versus 14.2 (p 0.17); patched sky 0.7 versus 0.6 (p 0.35); objects and stones revolt 0.7 versus 4.2 (p 0.73). Old craters, our control, show nothing either. None is a real signal. The check that mattered: the unrelated earth-diver creation story looked twice as common near craters on a raw count (27.7 versus 14.1 percent) simply because it is common in Siberia and North America, where several craters are. Shuffling within countries removed it (p 0.94). Without that control we would have 'discovered' a false link. What this does and does not say: the catalogue records widespread story types, not local place-legends. The known crater stories (Henbury, Campo del Cielo) are local legends tied to one spot, which this catalogue was never built to capture. So the result is: impacts left no broad footprint in world mythology, not that nobody remembered them locally.

• Test local place-legends instead: gather stories attached to named places within 50 km of each young crater and compare with random places
• Same method for volcanoes: do flood-of-fire or darkness motifs cluster near Holocene eruptions?

The lost-sister stories date from 100,000 years ago, when Pleione stood clear of Atlas

Checked 25 October 2026. The geometry holds: Pleione was about 8.6 arcmin from Atlas 100,000 years ago, against 5.0 now. But the visibility argument does not: (1) six stars are seen because six Pleiads are clearly bright and the 7th is less than half as bright as the 6th, the biggest step in the cluster; glare is not needed to explain six. (2) Stars only 0.36 magnitudes fainter than Pleione already sit far from any glare (Celaeno at 10.6 arcmin from Electra, HD 23753 at 40 arcmin) and most people still do not see them, so lifting the glare would add a 7th star only for eyes whose limit falls in a narrow 0.36-magnitude band. (3) Pleione's own brightness has changed by about half a magnitude within a century, more than that band, so the drift over 100,000 years is not the deciding factor. The 100,000-year date therefore does not follow from the astronomy. The published critique we found (Tales of Times Forgotten, 2026) accepts the astronomy and argues only from history, so this point appears to be new. Not yet seen: Schaefer's comments (quoted in Live Science).

The Odyssey's sky clues single out the eclipse day, 16 April 1178 BC

Checked 25 October 2026. Two weaknesses, both measurable: (1) with the clues the paper actually searched with, some date fits about every 64 years, so finding one or two in a 135-year window is what chance gives (18 March 1189 BC fits as well as 1178); even with the extra equinox clue the rate is about one every 280 to 470 years, 4 to 7 times commoner than the paper's 'one day in 2,000 years'. (2) The eclipse was probably not total at Ithaca: about a 31 percent chance, partial with both NASA's and the paper's own Earth-rotation value. The philological objections (Gainsford 2012: the scene is indoors, nobody else sees it, Hermes as Mercury is unattested before Plato) still stand. I found no published rerun of the date search.

Each Maya city fell silent during a local dry spell

Tested 25 October 2026. Pre-set test: the decade ending at each of the 89 last monuments was no drier than chance in the Yok Balum record (p 0.46). Exploratory, 20-year periods: the number of cities ending tracks dryness (r +0.58, p 0.06) only because of 780-799, and the share of still-active cities ending runs the wrong way (r -0.41). The peak of shutdowns (780-799) came before Cariaco's dry century (820-919), and in the cave record the last cities ended in wet years. Both records agree the collapse fell in a drier era that ended about 920 (already published); neither ties particular cities to particular dry spells. Dating caveats: monuments on fixed calendar dates, stalagmite age errors of a few years.

Korean dim-Sun records track volcanic eruptions (Goryeo period, 918 to 1392)

Tested 25 October 2026 (script: scripts/goryeosa_dimsun.py). Parsed 8,243 dated sentences from the Goryeosa omen and astronomy volumes and found 30 entries of a Sun 'without light', red, blood-coloured or dim, in 21 different years. Compared with the 12 eruptions of over 5 million tonnes of sulfur in the eVolv2k ice-core list. Result: only 2 of the 21 dim-Sun years fall in the year or two after a big eruption, about what chance gives (p 0.2 to 0.3). Most entries fall in the 2nd and 3rd lunar months, March and April, the season of dust storms from the Gobi. The record also misses most big eruptions: of the nine largest, it caught only 1108 (three red, lightless springs in a row, 1109 to 1111, matching the 1108 to 1110 cluster) and Samalas 1257 ('the Sun was blue, without light', then 'red like blood', in early 1258). It has nothing after 1171, 1182, 1230, 1276, 1286 or 1345, and nothing in 1285 to 1288 for our 1286 puzzle. Verdict: in the Goryeo period these records are mostly dust and cannot find new eruptions, though they confirm the very largest.

1261: no sky record falls in the right window, and the obvious one was already considered

Miyahara et al. 2022 measured a small rise into the 1262 ring. By their tree's timing, the burst must have come between about August 1261 and mid 1262. They considered the Chinese red glow of 9 February 1261 and judged it too early, which our day-name check confirms (it is firmly February 1261). Our other records miss the window too: Korea's three glows were October to December 1260, too early; Japan's flickering lights were February 1263, too late. Two remain unplaced: the Songshi white vapour at Lin'an on 16 August 1262, right at the late edge, and the Salzburg glow of 1262, which has no month. Neither is strong. The broader point still stands: 1257 to 1263 was a busy, glow-filled time, partly from an active Sun and partly from volcanic haze after Samalas.

• Read Miyahara 2022 in full: did they already use these aurora records?
• Wang 2021 Korean catalogue for 1260 to 1263
• Salzburg annals (MGH Scriptores 9, pages 758 to 810) for the 1262 wording and month

Pinatubo's Buag eruption made the 1453 sulfate signal

Checked 25 October 2026. In the Smithsonian list, Pinatubo's Buag eruption (VEI 5, about 1450 +/- 50) is the only large northern tropical eruption whose date fits; recalibrating its five radiocarbon ages with IntCal20 gives 1438 to 1454 (68 percent), and it was about the size of 1991, which matches the ice. No paper we found has proposed it. But the sulfur isotopes (Burke et al. 2023) show the first 1453 sulfate reached Greenland below the ozone layer, so the main volcano was outside the tropics, near or upwind of Greenland. A Philippine eruption cannot do that. So Pinatubo is not the main source. One loophole, a long shot: the small Antarctic sulfate peak in 1453 is hard to explain with a purely northern eruption, and in 1600 Burke's team found two eruptions at once (one northern extratropical, plus Huaynaputina in the tropics). If 1452/53 was also a double event, Pinatubo could be the tropical partner. Test: look for Pinatubo-type dacite glass, or a stratospheric sulfur-isotope signal, in the small 1453 peak in Antarctic ice.

Daily Korean records can date the 1452/53 eruption to the month

The tree rings put the eruption between late summer 1452 and early summer 1453. Tested 25 October 2026 with the Annals of the Joseon Dynasty (scripts/sillok_days.py and scripts/sillok_sky.py), read day by day for 1447 to 1458, about 3,600 days with entries. Result: the Annals of this period never describe the colour or brightness of the Sun: not one dim, red or lightless Sun in twelve years. They record only 3 lunar eclipses in that time, though many more were visible from Korea. The total eclipse of 16 November 1453 is there, but only as 'the Moon was totally eclipsed' (月食旣), with no word on how dark it was. Fog entries cluster in 1451 to 1454 (14 entries, including a 'dark fog, people unrecognisable a few steps away, four days in all' from 20 November 1452 and arm's-length fogs with rime ice in December 1452 to February 1453), but they start in 1451, before the eruption, and appear only under Kings Munjong and Danjong (none in 1447 to 1449 or 1457 to 1458), so they track what the court chose to write down, not the volcano. Sun haloes swing from 1 a year to 36 a year in the same way. Verdict: the Annals are too thin a sky record in the 1450s to date this eruption. Ming sources also give no dim Sun for 1452 to 1453, only cold: 40 days of snow in Jiangxi in spring 1453 and the frozen winter of 1453 to 1454. Kuwae check: in 1459, after one of the largest eruptions of the millennium, the Annals also record no dim or red Sun and only a few haloes. Confirms the Annals of this period cannot see a volcanic veil.

Sweating sickness followed seed-boom years, as modern European hantavirus does

Modern Puumala hantavirus outbreaks in Europe follow a chain: a warm summer, a bumper beech and oak seed crop the next autumn, a vole boom, then human cases. We tested the first link with the summer temperature reconstruction: was the summer two years before an outbreak warmer than the summer three years before? France, 171 outbreaks at their own grid squares: slightly the opposite (minus 0.14 of a typical swing), chance of this high or higher 87 percent. England, 5 outbreaks: no difference (plus 0.01), 48 percent. A plain 'warm summer two years before' gave a hint in England (7 percent) but nothing in France (54 percent). Verdict: no support for the seed-boom version. If the sweats were hantaviruses, they did not follow the mast cycle that drives Puumala today, or the temperature grid is too coarse to see it.

The dancing plagues were ergot poisoning

Tested 25 October 2026 (scripts/ergot_climate.py). If the dances were ergot years they should look like the 117 recorded ergot epidemics: cold and somewhat wet. They do not. Over the 9 outbreaks the same summer was warmer than normal (+0.40; if they were ergot-type years a mean this warm would happen about 1 time in 70) and the summer before was drier than normal (-0.54; about 1 time in 100). Only 2 of 9 dances have an ergot epidemic within a year (1237 and 1374), close to what chance gives. The 1950s ergot argument for 1518 (Backman) assumed floods; the records show the opposite, a severe drought. Caveat: 9 outbreaks is few, and 1374 on its own looks more ergot-like (a wet summer before, ergotism in France in 1373).

Cocoliztli broke out in central Mexico after drought (within two years)

Tested 25 October 2026. In the Mexican Drought Atlas the central highlands were not dry in the year before the 14 epidemics (mean z +0.34). The 16th-century megadrought is strong in Durango, the northern record used in 2002, but in the central highlands 1540 to 1580 was one of the wettest periods of the last 600 years. Two central-Mexico records agree that the 1570s were wet there. The 1540s are disputed between records.

Sleepy sickness follows flu waves by about a year (Ravenholt and Foege)

Tested 25 October 2026 with US national annual death rates (scripts/el_flu.py). Year-to-year changes in encephalitis deaths do not follow changes in flu deaths a year earlier (1922 to 1938: r = -0.01). Caveat: Ravenholt and Foege used month of onset for 142 Seattle cases; national annual deaths blur a 12-month lag. England and Wales 1921 to 1937 agree: encephalitis one year after flu, r = -0.26 (the wrong direction).

Sleepy sickness and flu rise in the same years

Tested 25 October 2026 in two countries (scripts/el_flu.py). United States 1922 to 1938: same-year changes move together modestly (r = +0.43, p 0.03), but encephalitis rose in only 2 of 6 big flu years, and not at all in 1918. England and Wales 1921 to 1937: no link (r = +0.07, p 0.4); the 1924 epidemic came with a flu rise, but the big flu years 1922, 1927, 1929 and 1933 brought no rise in sleepy sickness (3 of 7 big flu years up). The US link does not replicate, so it is probably chance or a US certification habit. Scotland 1922 to 1937 agrees: r = -0.23. Three countries, one weak positive (US) and two nulls.

Europe missed the 1054 star because it was badly placed for European skies

Checked 25 October 2026: Rome and Constantinople saw it almost as high at dawn as Kaifeng, and from autumn it was up all night for months. The silence is about record keeping, not visibility: Latin Europe recorded only 1 of the 3 medieval supernovae, and an Arabic witness in Constantinople did note it.

1268: we thought nobody saw it, but Korea did, and it is already published

We had said the biggest 13th-century radiocarbon candidate had no sky witnesses, because the Yau 1995 catalogue has no East Asian aurora from 1264 to 1276. Miyahara et al. 2022 cite a Korean record of 15 February 1269 (from Abbott and Juhl 2016): a white band about 3 degrees wide across the night sky. They pair it with the 1268 to 1269 jump, and the timing fits their tree. So the puzzle was a gap in our catalogue, not in the sky. Lesson: one catalogue is never the whole record. And a second witness: reading the Goryeosa ourselves we found a red vapour in the west on 19 December 1268, inside the timing window and a stronger kind of glow than the February 1269 band. Miyahara's paper does not cite it, so it may be worth telling them.

• Check whether Goryeosa astronomical records thin out in the 1260s for political reasons (compare eclipses and comets in the same years)
• Japanese records for 1268 to 1270