Scientists have discovered that in the last 3,000 years there have been three sunshine "super storms" larger than what was observed in recent history.
A similar event today can have a very destructive effect on energy networks, communications, GPS systems and information technology, scientists warn.
Solar storms consist of high-energy particles released by explosions of the sun.
The rapid motion of the charged particles can wipe off sensitive satellite circuits and cause interference in the power grids, causing extensive power outages.
Two severe solar storms in modern times have caused major power cuts in Quebec, Canada, in 1989, and in Malmo, Sweden, in 2003.
But these events were the dwarfs of the solar storm that occurred in 660 BC.
Professor Raymond Musseller, from Lund University in Sweden, said: "If this sunshine happened today, it could have serious effects on our high-tech society."
The evidence of a solar super-storm came from the study of 100,000-year-old ice cores from Greenland.
Further research using deep cores and rising rings in the old trees confirmed two other massive sunshine that struck the Earth in 775 and 994 years.
The great solar storms, although rare, seem to be a naturally repetitive effect, say the researchers, writing in the journal Proceedings of the National Academy of Sciences.
"That's why we need to increase the protection of society from sunshine," Professor Muscheler said.
"Our research suggests that risks are being underestimated at the moment. We need to be better prepared."