The Bamboo Annals (Zhúshū Jìnián) is a historical chronicle of the history of ancient China, spanning ca. 2400 to 299 BCE.
A fragment of the Bamboo Annals. Image credit: National Diet Library of Japan.
“Historical auroral reports extend our knowledge of solar eruptions and long-term solar variability in the millennial time scale beyond the chronological coverage of instrumental observations, in the decadal to centennial time scales,” said Nagoya University researcher Hisashi Hayakawa and Dr. Marinus Anthonyvan der Sluijs from the University of Pennsylvania Museum of Archaeology and Anthropology.
“Such chronological extensions benefit the scientific community, increasing the number of case studies on extreme space weather events with lower frequency but higher potential impact on modern technological infrastructure.”
“So far, the earliest known datable reports of candidate aurorae have reached back to the 7th century BCE.”
“Beyond this time series, we analyzed a celestial report in the Chinese Bamboo Annals that has attracted little scientific interest, probably owing to the controversial interpretations for the physical identity and the chronology of the event.”
Dr. Hayakawa and der Sluijs examined the mention of a ‘five-colored light’ seen in the northern part of the sky on a night towards the end of the reign of king Zhao of the Zhou dynasty.
“We’ve located the observational site around Hàojīng (N34°14′, E108°46′) and dated the event to 977 or 957 BCE,” they said.
“On this basis, we’ve computed the equatorward extension of the auroral visibility as ≤39.0° in magnetic latitude and reconstructed the equatorward boundary of the auroral oval as ≤45.5° in invariant latitude.”
This would be the earliest datable record of an aurora known from anywhere in the world.
“The finding comes barely two years after that of the previous holder of this distinction — several records of candidate aurorae inscribed on cuneiform tablets by Assyrian astronomers in the period 679-655 BCE,” the authors said.
“Some scientists have also associated Ezekiel’s vision, which is now dated to 594 or 593 BCE, with auroral visibility in the Middle East, but caveat must be noted for its reliability.”
“Otherwise, another datable record of an early candidate aurora has been found for 567 BCE in the astronomical diary of the Babylonian king Nebuchadnezzar II.”
Why did it take so long for scientists to recognize the aurora in the five-colored light of this chronicle entry?
“One reason is that the Bamboo Annals had a chequered history. The original manuscript was lost, rediscovered in the 3rd century CE and lost again during the Song dynasty,” the authors said.
“In the 16th century, a variant text was printed in which the object in the sky was not a five-colored light, but a comet. Now the new study shows that this cannot have been the original reading.”
The team’s work was published in the journal Advances in Space Research.
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Marinus Anthonyvan der Sluijs & Hisashi Hayakawa. A candidate auroral report in the Bamboo Annals, indicating a possible extreme space weather event in the early 10th century BCE. Advances in Space Research, published online January 17, 2022; doi: 10.1016/j.asr.2022.01.010