Named Miyake events after the lead author of the first study to describe them, the spikes occur roughly once every 1,000 years or so and are recorded as sudden increases in the radiocarbon levels of ancient tree rings. The leading theory among scientists is that Miyake events are solar flares that are 80 times more powerful than the strongest flare ever recorded. But a new study...suggests that the origin of the radiation bursts could be even more mysterious than first thought. Scientists have spotted six Miyake events in tree rings so far, indicated by sudden, single-year leaps in the concentrations...