The brighter the eclipse, the clearer the atmosphere at that time, as the darker eclipse indicates a higher level of aerosol particles in the upper atmosphere, which is an indication of the volcanic activity that occurred in that period.
Before humans began heating the planet by burning fossil fuels in the 19th century, the Earth went through a cold period that lasted for several centuries and was known as the “Little Ice Age”.
Scientists believe this cold snap may have been caused in part by volcanic eruptions that have made the atmosphere hazy, blocking out some of the sun’s rays.
Records of these volcanic eruptions are few, and a large part of our information regarding them – which is sometimes incomplete or contradictory – is due to what was preserved in both the polar ice and tree rings.
And in New study Published in Nature, an international team of researchers led by Sebastien Gillet of the University of Geneva has found another way to learn regarding these historic volcanic eruptions, by studying descriptions of lunar eclipses in medieval manuscripts written in Latin by European monks or clerics. .
dark eclipse
According to the article Published by some of the team’s researchers on The Conversation website on April 6, the researchers collected hundreds of records of lunar eclipses from across Europe, the Middle East and Asia, and documented 187 eclipses between the years 1100 and 1300.
Sebastian’s team targeted descriptions that provide information regarding the brightness and color of the moon during the eclipse, and the researchers classified the color and brightness of the moon mentioned in each total eclipse, and found that the brighter the eclipse, the clearer the atmosphere at that time, as the darker eclipse indicates a higher level of particles. Aerosols in the upper atmosphere, which is an indication of the volcanic activity that occurred in that period.
The researchers compared the eclipse data with the behavior of aerosol particles in the atmosphere and observations of modern satellites, in addition to climatic evidence from historical tree ring records, so that they might then estimate the timing of the explosions more accurately than previous ice records and identify the explosions that reached the stratosphere that are likely to be It caused climatic cooling effects.
Lunar eclipse and the state of the atmosphere
When the sun, earth and moon are perfectly aligned, our planet prevents direct sunlight from reaching the surface of the moon. However, the Earth’s atmosphere deflects sunlight from our planet, and as a result some sunlight reaches the moon even during a total eclipse.
The earth’s atmosphere scatters sunlight, and acts as a giant color filter so that the more blue the light, the more it scatters, and this may explain why the sky is blue during the day and the sun is red at dawn and dusk.
During a total lunar eclipse, the Earth’s atmosphere filters sunlight reaching the moon, removing much of the blue and yellow light.
The state of Earth’s atmosphere at the moment of a total lunar eclipse controls how much light is filtered out.
How do volcanoes affect a lunar eclipse?
Imagine a total lunar eclipse while wildfires are raging outside, and the fires will pump smoke and dust into the Earth’s atmosphere, making the moon redder and darker during the eclipse.
Which brings us to the volcanic effect, whereby the largest volcanic eruptions pump massive amounts of material into Earth’s stratosphere, which can remain suspended in that layer for months.
According to the a report Published by the “Science Alert” website, the researchers found that the degree of brightness of the moon during its eclipse depends on the amount of material present / suspended in the stratosphere, and thus we conclude that the lunar eclipse will be significantly darker than usual in the months following a big explosion.
How do volcanoes affect the climate?
Volcanic eruptions can spew huge amounts of ash, sulfur dioxide, and other gases into the atmosphere. Eruptions can either cause cooling or warming (temporarily). The intensity of the effect depends on what the volcano ejects, how high the plume is, and the location of the volcano.
If sulfur dioxide reaches the stratosphere, it interacts with water vapor to form a long-term veil of sulfate mist, and this aerosol works with volcanic ash to prevent and scatter solar radiation, which often leads to cooling of the Earth’s surface.
For example, large volcanic eruptions such as the eruption of Mount Pinatubo in the Philippines in 1991 and the eruption of Tambora in 1815 in Indonesia led to a slight decrease in global temperature in the years following the eruption, with Europe and North America experiencing a “year without a summer” in 1816 following Tambora volcano eruption.
On the other hand, water vapor and carbon dioxide emitted by volcanic eruptions have a warming effect, but it is relatively small compared to carbon dioxide emitted by human activities, as all current volcanic emissions produce less than 1% of what human activities produce.
The past and future of volcanoes, eclipses and climate
In this study, the combination of historical observations, ice records and climate model reconstructions from tree rings made it possible to more precisely date those ancient volcanic eruptions.
It also allowed us to better understand their potential impact on the climate during the European Middle Ages, and this information can help us understand the role these eruptions may have played in the transition to the Little Ice Age.
It can be argued that for a future “dark” eclipse to occur, a more intense volcanic eruption would be required to put large amounts of aerosols into the stratosphere, which rises with the temperature of the atmosphere.
Source : The Conversation + Science Alert + Websites