There have been a lot of theories over the years about how Stonehenge was built. Moving massive stones ranging from 4 to 45 tons over hundreds of miles isn’t easy in modern times, and certainly was a challenge 4,500 years ago. The two leading theories–log rollers and wooden sledges greased with animal fat–both have detractors. Many archaeologists believe rollers would have left deep scars in the landscape and one can be found, while reenactments with sledges have shown it would take hundreds of people to move the largest stones.
Now National Geographic reports a new theory. British graduate student Andrew Young thinks grooved wooden rails fitted with stone balls would have made an easy surface on which to move the stones. The balls acted like ball bearings and giant stones could have been pulled along on top. He tried it out with a team of seven people and found they could easily move a load of four tons. Only a relatively short length of track would be needed because the rails and balls could be pulled up once the stone passed and placed at the front.
He got the idea by studying mysterious stone balls found near stone circles in Scotland. They didn’t appear to have any purpose until he noticed they’re all exactly 70mm (3 inches) in diameter, suggesting they were part of some greater mechanism.
It’s an interesting idea, but this former archaeologist isn’t convinced yet. No stone balls have been found in England. Young says old-growth wood could have worked just as well and wouldn’t have survived, and that’s possible, but civil engineer Mark Whitby told National Geographic that the biggest stones in Stonehenge would have crushed the balls into the tracks. A larger-scale demonstration is being planned to study this issue.
Generally the KISS method (Keep It Simple, Stupid) points to the most probable solution. Wood was plentiful and making smooth rollers out of tree trunks would have been the easiest solution. Rollers and a bunch of strong prehistoric Britons, helped by teams of oxen, would have been the cheapest and least technologically demanding way to move the stones. While this would have left marks on the land, it’s an open question whether they’d still be visible after 4,500 years of weathering.
The KISS method also explains why aliens didn’t build Stonehenge.
The balls idea is still worth investigating, and considering that Young has come up with such an innovative and perhaps correct answer to a major archaeological mystery while still a PhD student in biosciences hints that I’ll be writing more about him in the future.
[Photo courtesy Mister Rad via Gadling's flickr pool]