Scientists have pinpointed a colossal surge in radiocarbon levels 14,300 years ago, uncovering evidence of a large solar storm, the most powerful on record.
A comparable event today would have devastating consequences for modern technology, potentially incapacitating satellite telecommunications systems and causing widespread electricity grid failures. The collaborative research provides fresh insights into the sun's extreme behavior and threats to Earth.
Ancient Trees in Eroded Banks
Researchers from the Collège de France, CEREGE, IMBE, Aix-Marseille University, and the University of Leeds conducted the study, analyzing radiocarbon levels in ancient trees preserved in the eroded banks of the Drouzet River in the Southern French Alps.
The subfossilized tree trunks were dissected into individual tree rings, revealing an unprecedented spike in radiocarbon levels precisely 14,300 years ago.
By correlating this spike with beryllium measurements from Greenland ice cores, the team postulates that it resulted from a massive solar storm ejecting substantial volumes of energetic particles into Earth's atmosphere.
Edouard Bard, Professor of Climate and Ocean Evolution at the Collège de France and CEREGE and the study's lead author, explained that radiocarbon is continuously produced in the upper atmosphere through reactions initiated by cosmic rays.
"Recently, scientists have found that extreme solar events, including solar flares and coronal mass ejections, can also create short-term bursts of energetic particles which are preserved as huge spikes in radiocarbon production occurring over the course of just a single year," Bard said in a press statement.
Severe solar storms can cause substantial havoc on Earth, with the potential for permanent damage to transformers in our electrical grids, resulting in prolonged and extensive blackouts.
Miyake Events
Over the past 15,000 years, nine of these extreme solar storms, referred to as Miyake Events, have been documented. The most recent confirmed instances took place in 993 AD and 774 AD.
Remarkably, the newly discovered storm from 14,300 years ago dwarfs its predecessors, measuring roughly twice their magnitude. The precise mechanisms governing these Miyake Events remain enigmatic, as they have never been directly observed.
This underscores significant gaps in our comprehension of the sun's behavior and its potential perils to Earth. Questions persist about what triggers such extreme solar storms, their frequency of occurrence, and the feasibility of predicting them.
The Carrington Event in 1859, the largest solar storm observed directly, wrought havoc on Earth. It obliterated telegraph machines and illuminated the night sky with a brilliant aurora.
Nonetheless, the Miyake Events, encompassing the recently unearthed 14,300-year-old storm, would have wielded a magnitude of power orders of magnitude greater. Radiocarbon analysis stands as an invaluable method for delving into Earth's history and piecing together critical events it has weathered.
Cécile Miramont, Associate Professor of Paleoenvironments and Paleoclimates at IMBE, Aix-en-Provence University, underscored the extraordinary nature of discovering such an assembly of preserved trees.
"By comparing the widths of the individual tree rings in the multiple tree trunks, we then carefully pieced together the separate trees to create a longer timeline using a method called dendrochronology," Miramont said.
"This allowed us to discover invaluable information on past environmental changes and measure radiocarbon over an uncharted period of solar activity," she added.
The team's findings were published in Philosophical Transactions of the Royal Society A.
