US, WASHINGTON (ORDO NEWS) — The nature of the strange phenomenon that occurred almost a thousand years ago was able to determine.
Almost a millennium ago, a giant cloud of sulfur-rich particles entered the Earth’s atmosphere. This darkened the sky for several months or even years before the particles settled on the ground.
Scientists found this out by drilling and analyzing ice cores. Aerosols of sulfur formed during volcanic eruptions and reaching the stratosphere were found in the samples. Ice can hold evidence of volcanic activity for an incredibly long time. However, determining the exact date of the event, traces of which were found in the cores, is not so simple.
Scientists previously suggested that sulfur deposits were the result of a major eruption in 1104 of the Icelandic volcano Hekla, which in the Middle Ages was called the “Gateway to Hell”. But these data are refuted by the results of a new study conducted by a group of scientists led by paleoclimatologist Sebastien Guillet from the University of Geneva in Switzerland.
According to researchers, Hekla could not be responsible for air pollution, since core deposits were from a later period – from the end of 1108 to the beginning of 1113. Scientists turned to historical documents in search of old descriptions of unusual lunar eclipses, which could correspond to changes in the stratosphere during major eruptions.
“Atmospheric optical phenomena associated with volcanic aerosols have attracted the attention of chroniclers from ancient times. In particular, the declared brightness of lunar eclipses can be used both for detecting volcanic aerosols in the stratosphere and for quantifying the stratospheric optical depths after large eruptions,” the authors of the study.
According to NASA records based on astronomical retro-calculation, seven total lunar eclipses could be observed in Europe in the first 20 years of the last millennium, between 1100 and 1120. At the same time, one of the medieval testimonies speaks of an exceptionally dark moon, observed in 1110.
“On the fifth night of May, the brightly shining Moon rose, and then its light gradually diminished, and as soon as night fell, it completely disappeared, neither light nor ball was visible,” says the Peterborough Chronicle, one of the digitized English annals.
Since then, many astronomers have discussed this mysterious and unusually dark lunar eclipse. Centuries later, the English astronomer George Frederick Chambers (1841-1915) wrote about it: “Obviously, this [eclipse] was an example of a black eclipse when the Moon becomes completely invisible and does not shine with a familiar copper hue.”
Despite the fact that this event is well known in the history of astronomy, researchers never assumed that it could have been caused by the presence of volcanic aerosols in the stratosphere, although this is the most likely reason, a new study suggests.
The most likely culprit for the “disappearance of the moon,” scientists call the Asama volcano in Japan, which erupted for several months in 1108. A diary entry left by a Japanese statesman describes this event as follows: “There was a fire at the top of the volcano, a thick layer of ash in the governor’s garden, all rice fields were unsuitable for cultivation. We have never seen anything like it in a country. This is a very strange and rare thing.”
The authors also studied data on tree rings, which showed that 1109 was exceptionally cold (about 1 degree on average in the northern hemisphere). Researchers found other evidence of cooling, crop failures and famine during this period, including Europe.
Scientists note that this combined evidence shows how a forgotten series of volcanic eruptions in 1108–1110 caused terrible consequences for humanity. Now researchers are opening them from a new perspective.
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