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A pair of scientists connected with the National Institute of Polar Research and other institutions in Japan have utilized ancient literature and contemporary data to map the shifting auroral zone over the last 3 millennia. By finding historic accounts from cultures around the world theyve created a video covering three thousand years of auroral drift.
Theyve published their research in the Journal of Space Weather and Space Climate. The papers title is “Auroral zone over the last 3000 years” and the first author is Ryuho Kataoka, associate teacher at the National Institute of Polar Research.
Rebuilt auroral zone over the last 3000 years.
“The precise understanding of the auroral zone over the past 3,000 years– via worldwide old witness record of auroras, consisting of those even from low-latitude Japan– helps us understand the extreme magnetic storms,” said first author Kataoka in a press release.
Science contributed along with ancient writings in this study. Paleomagnetism is the study of magnetic evidence in rocks, and the scientists utilized paleomagnetic designs to map Earths auroral zone in time. The auroral zone is an oval shape that moves with time. Most auroras occur in a band about 20 to 30 degrees from the poles. However that zone can stretch even more into middle latitudes when effective solar storms occur; even over areas such as Japan.
“The auroral zone changes gradually, and the contortion and sporadic growth of the auroral oval are taped in historic files over a thousand years from throughout the world,” Kataoka stated.
Approximated international shape of the auroral zone in 1200 AD (blue) and 1800 ADVERTISEMENT (red). Contours are apex field intensities of 49, 173, 474, and 6178 nT, corresponding to 70, 65, 60, and 40 magnetic latitudes.
Among the historic files the researchers made use of is an Old Norse text called “The Kings Mirror.” Its 70 chapters long and is written as a discussion in between dad and child. In this case, the dad is Haakon IV Haakonsson and the boy is Magnus Haakonsson. The text was intended to instruct Magnus in royal affairs and prepare him for reign. Its mainly worried with matters of the court, morality, strategy, trade, and chivalry and methods. The Kings Mirror also includes descriptions of auroral activity over Greenland in 1200-1300 AD.
The Nippon Kisho-Shiryo has a cluster of auroras around 1200 AD, which matches what The Kings Mirror programs. In the list below century, paleomagnetic data reveals that the auroral zone moved away from Japan and settled over Greenland.
Reconstructed auroral zone in 2010 AD (left) and 1200 ADVERTISEMENT (right). Image Credit: Kataoka and Nakano 2021.
Paleomagnetic data shows another auroral dip over the United Kingdom throughout the 18th century, which also matches up with written accounts.
Left: Auroral isochasm by Fritz (1881 ). The compiled files were from 1700 to 1872 AD.Right: Reconstructed auroral zone in 1800 ADVERTISEMENT (black) and possible contortion by a 170-year integration for the time period between 1700 AD and 1870 ADVERTISEMENT (red).
One of the researchers objectives was to learn if witness accounts of auroras match up with paleomagnetic data. Particularly, they desired to see if scientific information supported the concept that the 12th century was the very best time in Japan to witness auroras. They had the ability to verify that, and more.
“We concluded that the 12th and 18th centuries were outstanding periods for Japan and the United Kingdom, respectively, to observe auroras in the last 3,000 years,” Kataoka said in a press release.
Paleomagnetism is the study of magnetic proof in rocks, and the scientists utilized paleomagnetic designs to map Earths auroral zone over time. The auroral zone is an oval shape that moves over time. Estimated international shape of the auroral zone in 1200 AD (blue) and 1800 AD (red). The Kings Mirror also consists of descriptions of auroral activity over Greenland in 1200-1300 AD.
In the list below century, paleomagnetic information shows that the auroral zone moved away from Japan and settled over Greenland.
Auroral activity on Earth varies gradually. As the magnetic poles drift, auroras can appear at different latitudes around the world. Solar activity likewise impacts them, with powerful solar storms pushing the auroras further into mid-latitudes.
In an effort to much better understand how auroras move, how theyll relocate the future, and when effective solar storms might posture a danger, a team of scientists have actually tracked auroral activity for the last 3,000 years.