Long Lost Ancient Stone Circle on Remote Scottish Island May Have Been Built to Attract Lightning

A long lost ancient stone circle on a remote Scottish island may have been created to attract lightning, scientists have said. The neolithic structure, on the Outer Hebrides, was found to contain a stone that had a star-shaped magnetic anomaly that can be explained by it being struck by lightning multiple times in the same spot, or by one huge strike.

The 4,000-year-old monument, which had been buried by peat bogs, was discovered using remote sensing techniques that allowed researchers to map the landscape below the surface.

It was found in the Loch Roag area of Lewis. This site contains the Calanais Great Circle—a neolithic stone monument that has been designated a UNESCO World Heritage site. The area is known to contain over 15 other potential stone circles and these are divided into groups according to their elevations. Studying these monuments is difficult, however. The landscape is covered in peat, and over the years swallowed many of the stones.

In a study published in the journal Remote Sensing, researchers led by Richard Bates, from the University of St Andrews, have now identified a circle of standing stones that appears to have been used as lightning rods. The site—Site XI or Airigh na Beinne Bige—is only known from one stone exposed on a hillside overlooking Calanais. Their remote sensing technique, however, allowed the team to find the rest of the monument and map it. In doing this, they found two features that had an unusual magnetic signature—a signature that is associated with lightning strikes.

One of these features was found at the center of a large stone. The team notes that in the U.K., lightning strikes are often associated with large, tall features like trees, high buildings and posts. Satellite data from the last 10 years shows this region of Scotland experiences 0.1 to one lightning strike per kilometer squared (0.3 square mile) per 10 years.

"Lightning is well-established not to strike uniformly on a landscape," they wrote. "Lightning ... effectively searches for and locates positions of charge build-up or, for effective discharge/grounding, places on a land surface. Persistent features such as trees, stones, or conductive minerals will tend to be struck multiply over time. At Site XI, no upstanding feature exists today although the site itself is very exposed."

Calanais Great Circle
The Calanais Great Circle, on the Isle of Lewis, Outer Hebrides, Scotland. Other stone circles at the site have been buried by peat since they were built thousands of years ago. Peter Thompson/Heritage Images/Getty Images

They said the presence of lightning strikes on the stone should be "carefully reviewed," but add that " it is not impossible that lightning strikes may have cultural significance." The study argues that the stone circle may have been "deliberately" built in a position above the monument complex because it had a better chance of being hit by lightning.

They also say there is the possibility that a large tree or natural stone that acted as a lightning rod may have once existed at the site. "If such features had some cultural significance to the people on the island, then the stone circle might memorialise such a feature or simply record a natural event that was noticed and judged significant by contemporary communities," the team wrote.

In a statement, Bates said: "Such clear evidence for lightning strikes is extremely rare in the UK and the association with this stone circle is unlikely to be coincidental. Whether the lightning at Site XI focused on a tree or rock which is no longer there, or the monument itself attracted strikes, is uncertain.

"However, this remarkable evidence suggests that the forces of nature could have been intimately linked with everyday life and beliefs of the early farming communities on the island."

Study author Vincent Gaffney from the U.K.'s University of Bradford, added: "The dramatic results of survey on Lewis demonstrate that we have to understand the landscapes that surrounds these ritual monuments and the role that nature and natural events, including lightning, played in creating the rituals and beliefs of people many thousands of years ago."

Bates told Newsweek they now plan to study the site with "micro-scale measurements" to find out more about the magnetic signatures of the stone. "This will hopefully tell us if it has been preferentially hit by lightning," he said. "The data will also help us find out exactly where the stone came from within the surrounding landscape. We are conducting similar investigations at other stone circles in the UK—Stonehenge for example—and at other important sites such as Carahunge in Armenia."

This article has been updated to include quotes from Richard Bates.