Were Stonehenge’s Builders Guided by the Moon?

Researchers are studying the monument’s connection to a celestial event that occurs every 18.6 years

Henge and Moon
Stonehenge was constructed in stages beginning about 5,000 years ago. James O. Davies / English Heritage

Historians have long known that Stonehenge—England’s famed prehistoric rock circle—was built with the path of the sun in mind. On each solstice, spectators visit to watch the sun shine through the monumental stones. Now, researchers think that Stonehenge’s builders may have also considered the moon.

Experts from English Heritage, the Royal Astronomical Society and several universities in England are beginning a new project examining Stonehenge’s potential connection to a celestial event known as a major lunar standstill: the period when the moon’s rise and set are the farthest apart from each other along the horizon. This event occurs just once every 18.6 years. The next one will begin this year and last until 2025.

“Stonehenge’s architectural connection to the sun is well known, but its link with the moon is less well understood,” says Clive Ruggles, an archaeoastronomer at the University of Leicester, in a statement from English Heritage.

Stonehenge’s original four Station Stones—small boulders that formed a rectangle around the structure—“align with the moon’s extreme positions,” he adds. “Researchers have debated for years whether this was deliberate, and if so, how this was achieved, and what might have been its purpose.”

While the monument's relationship with the sun's cycles is well-known, researchers are now studying its connection to the moon. Andre Pattenden / English Heritage

Stonehenge was built in several stages beginning about 5,000 years ago. Made of interlocking boulders, the monument is “the most architecturally sophisticated and only surviving lintelled stone circle in the world,” per English Heritage, which manages Stonehenge and other British monuments. Most historians agree that builders purposefully aligned the stone circle with the movements of the sun, which anchored their belief system, and that they performed burials on site.

Researchers think that at least one major lunar standstill occurred during the earliest stage of Stonehenge’s construction, “potentially influencing the monument’s design and purpose,” per English Heritage. The long sides of the Station Stones’ rectangle are oriented toward “the southernmost moonrise at the major standstill.” Additionally, between 2500 and 3000 B.C.E.—centuries before the large stones were installed—people buried cremated remains in a cluster in the southeastern portion of the site, “in the direction of the most southerly rising position of the moon.”

As BBC News’s Sophie Parker writes, “The theory is that these lunar movements might have been noticed in the early phase of Stonehenge and gone on to influence its later design.”

Beginning this spring, a team of archaeoastronomers—experts in historical understandings of astronomy—will study this idea onsite.

“Observing this connection firsthand in 2024 and 2025 is crucial,” says Amanda Chadburn, an archaeologist at the University of Oxford, in the statement. “Unlike the sun, tracking the moon’s extremes isn’t straightforward, requiring specific timing and weather conditions. We want to understand something of what it was like to experience these extreme moonrises and sets and to witness their visual effects on the stones.”   

Moon touching
A major lunar standstill occurs once every 18.6 years. Andre Pattenden / English Heritage

Stonehenge’s builders belonged to cultures guided by celestial events, so it makes sense that they would take a major lunar standstill seriously. The light of the moon may have been helpful for tasks like hunting, and its cycles “provided an ideal way to mark the passage of time and organize events and festivities,” according to English Heritage.

During a major standstill, the moon touches parts of the horizon the sun never reaches. Experts think this unusual sight may have seemed significant to cultures tracking the movements of celestial bodies.

“People have been conscious of the phase cycle of the moon going back tens of thousands of years,” says Ruggles, per the Guardian’s Steven Morris. “What I think may have been the case at Stonehenge—and this is what we’re interested [in exploring]—is that around the time of a major standstill, people noticed the moon rising or setting unusually far to the north or south, realized this was something special and came to venerate and eventually to monumentalize the directions concerned. You can imagine the elders recalling a time when they saw the moon in a sacred direction and then, a generation later, people’s awe at starting to see this again.”

Because major lunar standstills occur infrequently, they may have marked social, spiritual or religious celebrations, such as coming-of-age ceremonies, according to English Heritage.

“We’re excited to be working with a brilliant team of archaeoastronomers to explore the fascinating link between Stonehenge and the major lunar standstill,” says Jennifer Wexler, a historian at English Heritage, in the statement. “This opportunity allows us to delve deeper into the monument’s ancient mysteries and its relationship with celestial phenomena.”

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