One of the strongest known solar storms blasted Earth in 660 B.C. Traces of the storm preserved in ice cores and tree rings suggest the storm was about 10 times more powerful than the strongest solar storm recorded by scientific instruments.

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One of the strongest known solar storms blasted Earth in 660 B.C. Traces of the storm preserved in ice cores and tree rings suggest the storm was about 10 times more powerful than the strongest solar storm recorded by scientific instruments.