Scientists: Stonehenge Is Not a Calendar, It's Something More Mysterious

The rock formation of Stonehenge is a familiar site to many, though its purpose to ancient humans is unknown. Last year, a scientist proposed that the iconic monument was used to represent a calendar year. However, a new article published last week in Antiquity claims to debunk this theory, putting Stonehenge back in the realm of mystery.

According to the authors of the article—Giulio Magli from Politecnico di Milano in Italy and Juan Antonio Belmonte from Instituto de Astrofísica de Canarias and Universidad de La Laguna in Spain—“this proposal is unsubstantiated, being based as it is on a combination of forced interpretations, numerology and unsupported analogies.”

The “Stonehenge calendar” model argues that some of the monument’s stones represent a calendar based on a 365-day year divided into 12 months of 30 days each, including five “epagomenal days” with the addition of the leap year every four years. 

As the authors argue, there are three lines of faulty reasoning here. They first point out that the theory relies on numerology, which they define as a “pseudo-scientific form of reasoning that seeks hidden but meaningful relationships between numbers and concept.” They argue that the number 12 is “not recognisable in any specific feature of the monument,” and that the interpretation is likely prey to the selection effect in that the researchers focus on information relevant to what they want to be true. 

In terms of astronomy, the authors acknowledge that the solstice alignment is quite accurate. However, they note that “the slow movement of the sun at the horizon during these days therefore makes it impossible to control the correct working of the calendar.” They also emphasize that the idea of a “Stonehenge calendar” is based on cultural astronomical analogies––comparing the proposed Stonehenge calendar to Egyptian calendars. They claim this is a faulty analogy.

“Such monuments have not been found in Egypt, the supposed source of inspiration for the practice, and here is not a single piece of evidence to support the claim of an independent development in third-millennium BC Britain,” they write. 

In an email to Motherboard, Magli wrote that rather than reshaping the narrative, their work brings Stonehenge back to an interpretation that’s not  "modern-centered" (exact calendar and so on) but close to what we really know about Neolithic Britain: a place for the worship and the afterlife of the ancestors.”

The authors also emphasized the importance of well-trained researchers working on such projects. 

“We believe that matters such as ancient calendars, astronomical alignments and cultural astronomy should be reserved to specialists, trained in the subject, and not left to researchers from other disciplines, however renowned and knowledgeable in their own fields,” they write. “Multidisciplinarity and collaboration offer the most effective way forward.”

The author of the study that the researchers were commenting on, Timothy Darvill from Bournemouth University, did not respond to a request for comment in time for publication. 

According to Darvill, the article does not undermine the essential model of the sarsen structures at Stonehenge being constructed as a manifestation of a perpetual solar calendar. 

“The rather minor issues raised, in relation to marking and naming the months for example, are all unresolved questions that I recognised and commented on in the original article and which in the present state of archaeology at the site we cannot yet answer,” he wrote. "Their major beef seems to be in relation to the suggestion (and it was only a suggestion for further work) that the basic structure of the Stonehenge calendar might in some way derive from the Egyptian Civil Calendar that developed in the eastern Mediterranean in the early third millennium BC.”

While Stonehenge’s purpose is still a mystery, other research suggests it could have functioned as a ceremonial landscape  to honor dead ancestors. 

"It is important to try to think in the way the builders did, with a deep respect for their motivating ideas," Magli said.

Update: This article was updated with comment from study co-author Giulio Magli and researcher Timothy Darvill.