A strange phenomenon took place in 1110, almost millennia ago, when the moon disappeared from the sky. A massive cloud rich in sulfur particles climbed to the stratosphere, making the skies dark for several months or even a few years. In the end, the sulfur fell on the ground.
This event happened, with the central proof being sulfur aerosols that were trapped in ice cores that have been extracted from massive glaciers. The sulfur aerosols were carried at great altitudes in the aftermath of volcanic eruptions.
While ice can preserve evidence related to volcanic activity over an extended amount of time, it can be quite difficult to identify the timeframe for a specific event that can be observed within the layers of the ice cores.
The puzzle of the moon disappearance from the sky solved
Previous research inferred that the sulfurous deposit might have been the remnant of a massive event that took place in 1104 when the Hekla volcano erupted. The theory seemed to be confirmed by the ice cores, but a new problem surfaced.
Several years ago, a study argued that a timescale which is called Greenland Ice Core Chronology is, in fact, time-warped. The scale was incorrect by up to seven years during the first millennium and up by four years during the next one.
The new data prompted a new study, and it appears that Hekla may not be a source of the sulfur that was observed in the ice cores. A new and fascinating bipolar volcanic signal associated with sulfate deposition has been observed from late 1108 to early 1113 in the Greenland samples.
Evidence that reinforces this approach has also been identified in a revised Antarctic ice core chronology. Many of the chroniclers of that time wrote about the event and how the moon disappeared from the night sky. Some of them wrote about the exceptional darkness that could be observed during lunar eclipses, which took place within the same timeframe.