The study of ice cores allows scientists to reveal unknown pages of the history of our planet, but the question of their dating is always acute. For example, a thin layer of sulfurous deposits discovered in Greenland, the so-called sulfate trail, was originally associated with the eruption of the Icelandic volcano Hekla, which occurred in 1104. But recent research has revealed serious glitches in the old timescale, several years in every millennium. So this is not Hekla, but where does the trace come from?
One way to detect a large volcanic eruption from a distance is to study the atmosphere for soot and dust. The more particles were thrown into the air, the worse sunlight penetrates to the planet's surface. This leads to the appearance of "bloody sunsets", a decrease in temperature, and recently another factor was discovered. As described in the Peterborough Chronicles, on May 5, 1110, the bright moon suddenly dimmed so much that it became completely black and disappeared from the firmament.
To obscure the bright light of the moon, to make it merge with the blackness of the night sky, you need an incredible amount of soot in the air. Or something else - astronomers have calculated that between 1100 and 1120 there were seven total eclipses of the moon. In the next century, George Frederick Chambers will describe this phenomenon, when, during an eclipse, the lunar disk becomes almost black instead of the color of dark copper. This is a phenomenon known to science, but before it was not associated with volcanic eruptions.
It remains only to find which volcano could be so "noted". The answer was found in the annals of a Japanese official, who wrote that in 1108 “There was a fire on Mount Asama, a layer of ash fell out in the daimyo's garden, which also covered the rice fields. We've never seen anything like this before. " Additional studies of tree rings on tree trunks indicate that 1109 was a very cold year, leading to crop failure, social upheaval and famine in Europe. All the pieces of the puzzle come together - the eruption of Asama volcano brought a lot of problems and made the Moon "disappear" from the sky.
A scientific article investigating this historical phenomenon has been published in Scientific Reports.