A Miyake event is a massive burst of cosmic radiation from the Sun that leaves a permanent chemical signature in tree rings and polar ice. These events are at least ten times more powerful than the strongest solar storm ever directly observed, and only six have been confirmed in the last 14,000 years. They’re named after Japanese physicist Fusa Miyake, who first identified the phenomenon in 2012.
How Tree Rings Revealed an Invisible Storm
In 2012, Fusa Miyake and colleagues at Nagoya University published a striking finding in Nature. By analyzing the carbon-14 content of annual growth rings in two Japanese cedar trees, they found a sharp spike between AD 774 and AD 775. The increase was about 12 per mille in carbon-14 content, roughly 20 times larger than what normal solar activity would produce. Nothing in the existing record of solar behavior could explain it.
That discovery launched a search for similar spikes in tree-ring records around the world. A second event was quickly confirmed at 993–994 CE. Since then, researchers have identified four more: around 664–663 BCE, 5259 BCE, 7176 BCE, and 12,450 BCE. Each one shows the same pattern: a sudden, dramatic jump in carbon-14 that appears simultaneously in trees across different continents, pointing to a global cause rather than a local one.
What Creates the Carbon-14 Spike
Carbon-14 is constantly being produced in Earth’s upper atmosphere. Cosmic rays, mostly high-energy protons from space, slam into nitrogen atoms roughly 10 to 13 miles above the surface, knocking out neutrons that then react with other nitrogen atoms to create carbon-14. This radioactive form of carbon gets absorbed by plants during photosynthesis and locked into their annual growth rings, creating a year-by-year record of cosmic radiation levels.
Under normal conditions, the Sun’s activity causes small, predictable fluctuations in carbon-14 production. During a Miyake event, however, a colossal flood of energetic particles hits Earth’s atmosphere all at once, producing a carbon-14 spike so large and abrupt that it stands out unmistakably in the tree-ring record, even thousands of years later.
Confirming Events With Ice Cores
Tree rings aren’t the only archive. Cosmic rays also produce two other radioactive isotopes, beryllium-10 and chlorine-36, in the upper atmosphere. Instead of being absorbed by plants, these isotopes wash down with rain and snow and accumulate in the annual layers of polar ice sheets. Sharp spikes of beryllium-10 and chlorine-36 in Antarctic and Greenland ice cores have been matched to all six known Miyake events, providing independent confirmation. This cross-referencing is what gives scientists confidence that the events are real, global, and caused by radiation from space rather than some quirk of individual trees or forests.
The ice core work has also opened a new path for discovery. Researchers at the Australian Nuclear Science and Technology Organisation have been systematically analyzing Antarctic cores, and continued work could reveal previously unknown events that tree-ring scientists could then follow up on.
What Causes Them
All six confirmed Miyake events have been linked to extreme solar proton events, essentially solar storms of extraordinary intensity. The Sun periodically hurls bursts of energetic particles into space, but Miyake events represent the extreme tail of that distribution. The evidence pointing to the Sun comes from the simultaneous appearance of beryllium-10 in ice cores, which rules out sources outside the solar system like supernovae or gamma-ray bursts from distant stars.
The 664–663 BCE event is particularly interesting because it arrived in two distinct pulses, producing a double spike in the carbon-14 record across multiple locations in northern Eurasia. This kind of structure suggests a complex eruption from the Sun rather than a single instantaneous blast. It also hints that these events may not all look the same, complicating efforts to define a single template for what a Miyake event “should” look like in the data.
How They Compare to Known Solar Storms
The most powerful solar storm in recorded history is the Carrington Event of 1859, which caused telegraph systems to spark and catch fire and produced auroras visible near the equator. That event is the standard benchmark for worst-case solar weather planning. Miyake events, however, are a different category entirely, producing particle blasts at least ten times larger than the Carrington Event. Nothing in the roughly 200 years of direct solar observation comes close.
This gap between what we’ve measured with instruments and what the tree-ring record reveals is one of the most unsettling aspects of Miyake events. The Sun is capable of far more violent outbursts than anything modern civilization has experienced.
What a Miyake Event Would Mean Today
If a Miyake-scale event struck today, the consequences would be severe. Power surges from the geomagnetic disturbance would threaten large portions of the global electricity network, particularly the high-voltage transformers that are difficult to replace and can take months or years to manufacture. Satellites in orbit could be destroyed outright by the radiation bombardment, disrupting GPS, weather forecasting, and communications.
The effects would reach down to the level of individual computer chips. High-energy particles passing through electronic circuits can flip individual bits from one to zero, a phenomenon called a single-event upset. This already happens occasionally under normal cosmic ray conditions, causing mysterious computer glitches. During a Miyake event, the rate would increase dramatically, potentially corrupting data and crashing systems across every sector that depends on electronics, which today means nearly all of them. Even well-shielded equipment could be vulnerable to a bombardment of this magnitude.
Can We Predict the Next One?
The short answer is no. With only six events spread across roughly 14,500 years, there isn’t enough data to establish a meaningful pattern. Researchers at the University of Arizona have specifically looked for cyclical behavior or correlations with known solar cycles and come up empty. As dendrochronologist Irina Panyushkina put it, tree rings give us the magnitude of these storms, but no detectable regularity that would allow forecasting.
The average gap between events works out to very roughly once every 2,000 to 2,500 years, but the intervals are irregular. The two most recent events, in 774–775 CE and 993–994 CE, were only about 220 years apart. The gap before that stretches back over 1,600 years to the 664–663 BCE event. This irregularity makes statistical prediction essentially impossible with current data.
Beyond the question of timing, scientists are still working to understand the full environmental impact. The radiation from a Miyake event doesn’t just create isotopes. It alters atmospheric chemistry in ways researchers are only beginning to trace. Understanding how these short-lived but powerful bursts affect Earth’s atmosphere as a whole is an active area of investigation, separate from the question of when the next one might arrive.
A New Tool for Dating the Past
One unexpected benefit of Miyake events is their value as precise chronological markers. Because the carbon-14 spike appears simultaneously in trees everywhere on Earth, finding it in a piece of ancient wood instantly pins that wood to a specific year. This has given archaeologists and historians an extraordinarily precise dating tool. Miyake event spikes have been used to anchor timelines for ancient Egyptian chronology, Viking-age artifacts, and other historical questions where conventional radiocarbon dating lacks the needed precision. A technique that normally gives dates within a range of decades can, when a Miyake spike is present, narrow the answer to a single year.