Scientists Say They Know Why the Moon Disappeared Completely in 1100 AD

The Earth’s satellite is hard to miss. It constantly rises night after night and one can always see it except for a few moments when dark clouds cover it for a short period of time. So you can imagine how frightened our ancestors were when they discovered that the Moon was no longer up there.

An international team of scientists claims to have solved the mystery behind the disappearance of the Moon in 1100 AD.

The incident itself was documented by an anonymous individual, who wrote: "On the fifth night in the month of May appeared the moon shining bright in the evening, and afterwards by little and little its light diminished, so that, as soon as night came, it was so completely extinguished withal, that neither light, nor orb, nor anything at all of it was seen. And so it continued nearly until day, and then appeared shining full and bright".

The unknown sky watcher noted that the clouds had nothing to do with the mysterious disappearance as stars were "shining very bright".

For more information about the incident, scientists turned to historical archives, which described 1100 AD as a disastrous year (we all can relate to it…). The Anglo-Saxon Peterborough Chronicle tells of earth-crops "damaged" by bad weather and tree-crops almost "ruined all over" the land. The Chronicle also talks about extreme temperature anomalies in the year 1109 AD, with thermometers in the summer dropping to -1 degrees Celsius (30.2 degrees Fahrenheit).

Researchers came to the conclusion that volcanic eruptions, which caused extreme temperature fluctuations in the past, are probably to blame for the Moon’s disappearance.

According to their study published on 21 April in the journal Scientific Reports, to corroborate their hypothesis they examined ice cores in Greenland and found an increase in sulfate, a component of volcanic ash, which began in late 1108 and early 1109. Scientists also studied tree rings from that period, which showed that 1109 AD was a very cold and wet year in Western Europe.

So who or rather which volcano is to blame for the disappearance of the Moon? Scientists don’t give a clear answer to that question. They simply say "closely spaced volcanic eruptions" that occurred between 1108 and 1110 AD produced a dust veil, which "hid" the Moon.

Researchers note one of the perpetrators is likely to be Mount Asama in Japan, which erupted in 1108 AD and contributed to the elevated sulfate in Greenland. The event was documented by a Japanese statesman, who wrote:

"According to a report from the province of Kōzuke, there is a high mountain in the middle of the province, Mount Asama. In the years 1065–1069, a slight smoke rose above the volcano but later became imperceptible. On 29 August, there was a fire at the top of the volcano, a thick layer of ash in the governor’s garden, everywhere the fields and the rice fields are rendered unfit for cultivation. We never saw that in the country. It is a very strange and rare thing".