Traces of an enormous solar storm that battered the atmosphere and showered Earth in radioactive particles more than 2,500 years ago have been discovered under the Greenland ice sheet. The Guardian reports: Scientists studying ice nearly half a kilometer beneath the surface found a band of radioactive elements unleashed by a storm that struck the planet in 660BC. It was at least 10 times more powerful than any recorded by instruments set up to detect such events in the past 70 years, and as strong as the most intense known solar storm, which hit Earth in AD775.
The discovery means that the worst-case scenarios used in risk planning for serious space weather events underestimate how powerful solar storms can be. Raimund Muscheler, a professor of quaternary sciences at Lund University in Sweden, and his team analyzed two ice cores drilled from the Greenland ice sheet and found that both contained spikes in isotopes of beryllium and chlorine that date back to about 660BC. The material appears to be the radioactive remnants of a solar storm that battered the atmosphere.
The scientists calculate that the storm sent at least 10 billion protons per square centimeter into the atmosphere. “A solar proton event of such magnitude occurring in modern times could result in severe disruption of satellite-based technologies, high frequency radio communication and space-based navigation systems,” they write in Proceedings of the National Academy of Sciences.
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