Glossary of Key Terms
536 AD Climatic Catastrophe: A global environmental disaster beginning around 535-536 AD, characterized by a prolonged dimming of the sun, extreme cold, crop failures, famine, and plague, believed to have significantly altered world history.
Dendrochronology: The scientific method of dating tree rings to analyze past climatic conditions and events.
Tree Rings: Annual growth layers within a tree's bark. Their width varies depending on environmental conditions (wide for good, narrow for bad), providing a chronological record of climate.
Crannogs: Wooden island forts, typically built in Ireland, which archaeological evidence suggests saw increased construction beginning in the mid-6th century, possibly as refuges during troubled times.
Annals/Chronicles: Historical records, often annual or chronological, compiled by ancient civilizations, used by David Keys to find written accounts of the 6th-century events.
Asteroid: A large, rocky body orbiting the Sun, smaller than a planet. A large impact on Earth could cause a dust veil and climatic effects.
Comet: An icy, rocky body that, when heated by the Sun, releases gases and dust, forming a "tail." A large impact could also cause a dust veil.
Airburst Explosion: An explosion that occurs when a meteor or other object enters the Earth's atmosphere and detonates in the air rather than impacting the surface. The 1908 Tunguska event is an example.
Ice Cores: Cylindrical samples of ice extracted from polar ice caps, which contain layers of snow that accumulate over time. These layers trap atmospheric chemicals, dust, and gases, providing a chronological record of past climate and atmospheric composition.
Sulfate Peak: An elevated concentration of sulfates found in ice core layers, indicating a significant amount of sulfuric acid in the atmosphere, typically a telltale signature of a major volcanic eruption.
Iridium: A rare chemical element often found in higher concentrations in the Earth's crust after an extraterrestrial impact (e.g., asteroid or comet), used as a marker in ice core analysis.
Krakatoa: A notorious volcano located between the islands of Sumatra and Java in Indonesia. Evidence suggests a massive eruption of Krakatoa around 535 AD was the cause of the global climatic catastrophe.
Caldera: A large, basin-shaped depression formed when the roof of a magma chamber collapses after a massive volcanic eruption.
Charcoal: Carbonized wood formed when organic material is subjected to high heat (e.g., from lava). It is used for carbon dating to determine the age of geological layers and past events.
Carbon Dating: A radiometric dating method that uses the decay of carbon-14 to determine the age of organic materials, such as charcoal.
