Evidence of the most powerful solar storm in history has been uncovered in an unlikely place: within the rings of a tree.
This immensely powerful solar storm is thought to have been at least 10 times as powerful as the Carrington Event of 1859, which caused chaos in the rudimentary telegraph system of the time.
New research has now found that a radiocarbon spike found within ancient tree rings in the French Alps reveals the full extent of the sun’s power and the potential danger it poses to us if a storm of this scale occurs today, according to a study published in the journal Philosophical Transactions of the Royal Society A Mathematical Physical and Engineering Sciences.
The researchers found a strange spike in radiocarbon within the rings of subfossilized trees dating to around 14,300 years ago.
“Radiocarbon is constantly being produced in the upper atmosphere by a chain of reactions initiated by cosmic rays (showers of high energetic particles coming from outside the solar system),” Tim Heaton, professor of applied statistics at the University of Leeds in England and co-author of the paper, told Newsweek. “Generally, the sun (and the Earth’s magnetic field) help shield us from the constant bombardment of these galactic cosmic rays—so that normally when the sun is more active, we get less radiocarbon being produced.
“However, in 2012, Fusa Miyake discovered a sudden and unexpected spike in radiocarbon levels in a Japanese tree from 774 AD. Initially, this was thought to have been caused by a supernova, but after more study, it was instead identified as being due to a huge solar storm on the sun,” Heaton said.
“Such extreme storms would throw out huge volumes of highly energetic particles from the sun. These energetic solar particles would have entered our atmosphere, leading to a sudden spike in radiocarbon production. Our storm is another Miyake event—but the largest that has ever been identified.”
The radiocarbon spike in the tree rings was found to line up with patterns in beryllium levels in Greenland ice cores, indicating that the spike was caused by a huge solar storm.
“We checked our 14,300-year-old radiocarbon spike by comparing it with beryllium-10 found in Greenland ice cores,” Heaton said. “Beryllium-10 is another chemical isotope that is produced in a very similar way to radiocarbon (in the upper atmosphere by the same energetic particles).
“The fact that the 14,300-year event was supported by both the radiocarbon and the beryllium-10 indicated that the massive production spike we found was genuine (and not noise). It also supported the solar origin of the event— i.e., a massive solar storm considerably bigger than any previously identified.”
Solar storms like this one and the Carrington Event are caused by solar flares, which are ejections of powerful X-rays from the sun.
“In general, a flare is a substantial release of energy from the sun and specifically an active region or sun spot,” Daniel Brown, an associate professor in astronomy and science communication at England’s Nottingham Trent University, previously told Newsweek.
“These are caused by magnetic field lines becoming more and more twisted storing energy like a rubber band, and at some stage, they snap and rearrange. That results in a massive release of electromagnetic radiation and also material from this region.”
The Carrington Event, thought to be the most powerful solar storm in modern history, caused widespread impacts to infrastructure in 1859, and led to an incredibly bright aurora in the night sky.
“In that strongest ever Carrington Event there were reports of telegraph lines sparking with the voltages induced in them,” Alan Woodward, a professor of computer science and space weather expert at England’s University of Surrey, previously told Newsweek.
A solar storm similar to the Carrington Event could lead to trillions of dollars worth of damages.
The solar storm measured in the tree rings is thought to be at least 10 times stronger than the Carrington Event, making it one of a class of extreme solar storms known as Miyake Events. Nine of these events have been identified as occurring in the last 15,000 years—the most recent of which occurred in 774 AD and 993 AD—but this new discovery may be the most powerful ever found.
“The Carrington Event is not identifiable by looking at past radiocarbon in trees—it did not leave a significant trace/spike in the radiocarbon record,” Heaton said. “It is thought that the Miyake events/storms are an order of magnitude bigger than the Carrington Event. Our 14,300-year-old storm is the biggest of all the Miyake event discovered so far (twice the size of the eponymous 774 and 993 AD storms first found by Fusa Miyake) so, at a guess, at least 10 times larger than the Carrington Event.”
This find therefore shows just how powerful the sun is capable of being and the possibility that a powerful solar storm like that could once again hit the Earth in the future.
“If similar solar storms happened today, they could be catastrophic for society as we are so reliant upon technology. In the worst-case scenario it has been estimated that the impact of such an extreme solar storm could cost us billions, or even trillions, of dollars in lost GDP,” Heaton said. “However, again, it is somewhat hard to know for sure as modern society has never directly experienced such storms and we don’t really know how resilient our current technology is.”
We need more research in this area to find out,” Heaton said. “Such an extreme storm could cause phenomenal damage to our electricity grids by creating geomagnetic disturbances (potentially destroying transformers and causing nationwide blackouts that last months). Additionally, the huge burst of energetic particles would rapidly hit our satellites in orbit, potentially destroying their solar panels and putting them permanently out of action. They would also generate a lot of radiation for astronauts which would be a big risk for their health.
“However, we don’t really know how resilient our current technology is to such huge events. This is the really big question—will our communication, electricity grids, and satellites mostly be able to withstand the impacts of such a storm and just suffer temporary effects before quickly coming back online? Or will they catastrophically fail?
“We really need more research to understand how resilient our existing technology is to such solar events and how we can best shield it from potential damage,” he said.
This new discovery does provide a new and exciting way to study the effects of past solar storms, which will help researchers get a sense of how common powerful events are.
“The really interesting thing is that currently we just don’t understand these massive Miyake storms: why they occur, how frequently, and if we can predict them. We urgently need more research to both better model the behavior of the Sun and improve our understanding of the risks it poses to Earth,” Heaton said.
“To date, we have now found 9 Miyake Events in the last 15,000 years (our storm is the largest found so far) so they are pretty rare. But the risks such an event might pose still mean it is critical to better understand their behavior so we can potentially mitigate their effects.”
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Update 10/09/23, 9:52 a.m. ET: This article was updated with comment from Tim Heaton.