Imagine a night sky without the bright, guiding light of the Moon. Now imagine that lasting for months, perhaps even years. This is what happened almost a millennium ago, in 1110, and now, scientists may have the reasons as to what caused this strange phenomenon.
Their findings were published in Nature Scientific Reports.
A huge upheaval occurred in Earth's atmosphere around a millennium ago: the skies turned dark after a massive cloud of sulfur-rich particles moved through the stratosphere, eventually landing down on Earth.
Ice has been preserving this evidence for incredibly long timescales, which helps scientists pinpoint exact dates of events that are visible in the layers of an ice core. It's no easy feat, however.
It's been confirmed that the Moon's disappearing act did occur, but different theories have been put forward over the years as to why.
Some assumed it was the sulfurous deposit left by a major 1104 eruption of Iceland's Hekla volcano that was to blame. However, another more recent research concluded that a timescale named the Greenland Ice Core Chronology 2005 (GICC05) was showing the wrong dates for some of the events.
The GICC05 information is what lead the new research team led by Sébastien Guillet from the University of Geneva to deduce that it could not have been the Hekla volcano's eruption that led to that specific phenomenon. The team then looked into medieval records that described dark lunar eclipses that could correspond to this event.
"The spectacular atmospheric optical phenomena associated with high-altitude volcanic aerosols have caught the attention of chroniclers since ancient times," the team writes in their paper.
"In particular, the reported brightness of lunar eclipses can be employed both to detect volcanic aerosols in the stratosphere and to quantify stratospheric optical depths following large eruptions."
The researchers discovered that another volcanic eruption occurred, in 1108 this time, when Japan's Mount Asama erupted. Combining witness accounts and observation of tree ring formations, and other historical documentation, the team suggests that this eruption could have lead to the strange occurrence.
These observations aren't proof enough to concretely say they lead to the occurrences, however, putting all the different information together has lead the scientists to believe these forgotten massive eruptions created huge consequences on humanity.