Deep in Greenland’s ancient ice sheet, scientists have uncovered evidence of an “enormous” solar storm that struck Earth more than 2,600 years ago, according to a new study. Our planet, the researchers add, would be ill-prepared in the likely event of another such cosmic bombardment.

The study, which was published Monday in the “Proceedings of the National Academy of Sciences” journal, was led by researchers from Sweden’s Lund University.

“If that solar storm had occurred today, it could have had severe effects on our high-tech society,” study co-author and Lund University geology professor Raimund Muscheler said in a statement. “That’s why we must increase society’s protection against solar storms.”

A solar storm occurs when explosions on the sun’s surface blast high-energy particles into the cosmos.

In today’s world, such storms can pose risks to electrical grids, satellites, communications systems and air traffic. In modern times, large solar storms led to widespread power outages in Quebec in 1989 and Sweden in 2003 -- but those storm, scientists say, pale in comparison to the one that occurred more than 2,600 years ago.

The radiation and magnetic shockwave unleashed from a solar storm “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,” the study said.

By drilling deep into 100,000-year-old ice in Greenland, researchers found radioactive evidence of an “extreme solar event” that occurred around the year 660 BC -- a period that coincides with the dissolution of the once-mighty Assyrian Empire, the construction of the Acropolis in Athens and the founding of Taoism in China.

According to the researchers, it is the third known case of such a massive solar storm hitting Earth in historical times. The others, they say, took place in 775 and 994 AD. During those events, humans would have been treated to a dazzling display of aurora. And although these kinds of enormous solar storms remain incredibly rare, one could very likely strike our planet again, but with much more devastating effects this time around.

“Such events represent a threat to modern society,” the study warned. “Therefore, better understanding the possible magnitudes and occurrence frequency of such events is of great importance for safeguarding space technologies and modern technological infrastructure.”

“Our research suggests that the risks are currently underestimated,” Muscheler added. “We need to be better prepared.”