Mystery Not checked yet 1560 BC 📍 Erlitou and the Yellow River plain

Why did the Xia dynasty fall (about 1600 to 1530 BC), and do the omens told of its end remember a real eruption?

Chinese tradition says the Xia, the first dynasty, ended when Tang of Shang beat King Jie at Mingtiao. Old books tie the end to strange skies and bad weather: Mozi (about 400 BC) says that under Jie 'sun and moon were out of time, cold and heat came mixed, the five grains scorched and died'; the Guoyu says 'the Yi and Luo rivers dried up and the Xia fell'; the Lushi Chunqiu (239 BC) says that after Tang won 'Heaven sent a great drought, five years without a harvest'. The 'current text' of the Bamboo Annals gives year-by-year entries: in Jie's 10th year 'the five planets moved in disorder', in his 29th 'three suns rose together', and a drought in Tang's years 19 to 24. Kevin Pang's JPL team (1989) used these to date the Thera eruption; David Pankenier tied the fall to a gathering of planets in 1576 BC. The capital at Erlitou (Yi-Luo valley) ends about 1530 to 1500 BC by radiocarbon.

Tests we ran on this

No sign 0.23 Do the Bamboo Annals' sky and weather entries land on ice-core eruption years more than chance? 3 of 8 entries hit; chance would give that about 1 time in 4. (decided before looking, 2026-10-26) · scoreboard
No sign 0.1 Was 1561-1546 BC unusually dry in the Qilian juniper rings? Somewhat: 50th driest of 486 sixteen-year windows. (decided before looking, 2026-10-26) · scoreboard
Passed 0.03 Are the rings narrow two years after each of the 11 eruptions? Yes at 2 years, but 7 lags were tried, so about 0.2 really. (chosen after looking, 2026-10-26) · scoreboard
No chance number Known answer: do the rings react to Aniakchak (1628 BC)? Yes: 1626 BC is one of the driest years (z -2.5), two years after. (decided before looking, 2026-10-26) · scoreboard
No chance number Could all five planets be seen together in 1576 BC? No: all five were close only when 4 degrees from the Sun; only four could be seen (agrees with Keenan). (decided before looking, 2026-10-26) · scoreboard

How it connects

This mystery we read it in JPL news release, 1 Dec 1989: Pang, Srivastava, Keston and Chou date Thera to the late 17th century BC from Chinese records of King Jie (dim sun, three suns, frost in the 6th month, seven-year drought), matched to the Greenland ice cores and tree rings of the time (AGU Fall Meeting 1989)

This mystery we read it in Zhang Xuelian and others 2022, 14C dating of the Erlitou site, Radiocarbon 64(4): 819-832; Erlitou culture about 1750-1530/1500 BC (2007 onward radiocarbon studies, as summarised on Wikipedia)

This mystery has this clue 1576 BC: all five planets within 26 degrees, but only 4 degrees from the Sun (unseeable); what could be seen in late December was four planets within 4.4 degrees

This mystery has this clue Ice cores: 1561-1550 BC was the busiest volcanic stretch of 1680-1500 BC (four eruptions in 12 years), and 1561 BC is the 2022 best guess for Thera

This mystery has this clue The current text's sky and weather entries land on ice-core eruption years no more often than chance (p = 0.23)

This mystery has this clue Juniper rings (Qilian Mountains, 1,400 km west of Erlitou): 1561-1546 BC was somewhat dry, with sharp dry years in 1558 and 1548 BC, from only 12 cores

This mystery has this clue Erlitou's last phase is dated about 1565-1530 BC, around the 1561-1550 BC eruptions; but the other proposed Xia-Shang boundary (about 1635-1610 BC) sits near the 1628 and 1611 BC eruptions too

This mystery has this clue No year-by-year rainfall record from the Yellow River plain reaches 1561-1550 BC; the published Qilian juniper record starts in 1500 BC (its raw cores go further: see the ring test)

This mystery has this hunch or step Pankenier's five-planet omen of 1576 BC: our sky check agrees with Keenan, only four planets could be seen

This mystery has this hunch or step The 'three suns' of 1561 BC fall in the same year as the 2022 Thera candidate, but only by the current text's own year count, which was built centuries later

This mystery has this hunch or step The early books remember failed harvests, mixed cold and heat and a five-year drought at the Xia's end; the ice cores show four eruptions in 1561-1550 BC, about when Erlitou ended

This mystery has this clue 'The five planets moved in disorder, at midnight stars fell like rain, the earth shook, the Yi and Luo dried up' in Jie's 10th year (1580 BC by the current text)

This mystery has this clue 'Three suns rose together' in King Jie's 29th year: 1561 BC by the current text's own year count

This mystery has this clue Mozi (about 400 BC): under King Jie 'sun and moon were out of time, cold and heat came mixed, the five grains scorched and died'

This mystery has this hunch or step Started the end of the Xia: the Bamboo Annals' 'three suns' lands on the 1561 BC eruption, but only by chance

This mystery has this hunch or step Looked for dry years in 1561-1550 BC in the raw juniper rings of the Qilian Mountains

This mystery has this hunch or step Checked the radiocarbon dates for the end of Erlitou; the Xia lead is parked