An intense blast of high-energy protons from the Sun pummelled the Earth in about 660 BC and left a distinct record of cosmogenic nuclei in the Greenland ice sheet. The discovery was made by an international team of scientists who say the event was one most powerful solar storms known to have struck Earth. The team calculates that the storm was about ten times more intense than any event that has occurred in the past 70 years. “If that solar storm had occurred today, it could have had severe effects on our hi-tech society”, says Raimund Muscheler of Sweden’s University...