Unravelling the mystery of megaliths
Dr Gail Higginbottom
Since completing her PhD in 2003 Dr Gail Higginbottom has continued her studies into the ancient megaliths of Western Scotland. Her work is revealing that early civilisations had a remarkable understanding of the connection between the sun and moon and their own world.
Extensive statistical analysis and advanced 3-D landscape models are proving that there was nothing random in the construction of hundreds of stone structures along Scotland's remote western region.
For the first time research by University of Adelaide PhD graduate Gail Higginbottom is confirming that ancient tribes had a complex and sophisticated system of observing solar and lunar cycles.
It's a conclusion which has left the archaeoastronomer excited and in awe.
She returned to the University in 2013 as a visiting researcher after some years trekking across islands and coastal regions to study a number of different stone structures.
By running her data on over 125 sites through a 3-D astronomy and landscape program developed by visiting Research Fellow Andrew Smith, she has discovered that the builders were meticulous in the selection of sites, placing them at precise distances from very specific horizon shapes.
Through this careful positioning the early astronomers were able to observe not only the summer and winter solstices but rare lunar events, and to watch the sun and moon setting and rising over particular landscape features.
Dr Higginbottom says carbon dating of some of the earliest megaliths shows they were built as long as 5000 years ago and she believes the science was then handed down through the ages and between tribal communities.
One of the most significant findings is that the majority of megaliths are closely aligned with the major lunar standstill - an event which takes place just once every 18.6 years when the moon reaches its maximum declination on the horizon and the new cycle begins.
"It's a complex process but these early civilisations knew exactly what they were doing," says Dr Higginbottom. "They carefully positioned their megaliths so that they could observe this rare event with the full moon rising and setting at its most northerly or southerly points along the slope or peak of a particular hill or range.
"Our analysis is proving that chance was not involved and it's very, very exciting. For some time now people have thought they understood these structures but the further I look into it I'm discovering it's more and more complex.
"These people were clearly very aware and capable."
The megalithic structures being studied by Dr Higginbottom were built between 1400BC and 800BC across Mull, Argyll, Lewis, Uist, Kintyre, and Islay and Jura.
Sometimes two or three are in sight of each other - between 50 and 1000 metres - and in these cases the positioning of one of these is often reversed with the most distant horizon found north of the site, instead of to the south. It's also quite common to have water in the south or, in the reverse sites, to the north.
"Added to this, one structure is usually oriented to the rising or setting of the solstitial sun and the others to the rising or the setting of the moon," says Dr Higginbottom. "Each of the sites within the group sees a slightly different version of where and when the sun and moon rises at these times.
"The closer horizons tend to curve around the monuments creating an amphitheatre-like affect, so when the moon or sun rises or sets they loom large and at night the moon can light up the local ground and bathe the stones in light. This is particularly common on the Isle of Mull."
Dr Higginbottom's studies also indicate that even when just one monument was erected, the landscape settings were carefully chosen by the megalith builders to allow a joint celebration of the summer solstice and accompanying full moon at opposite sides of the sky.
A possible link between megaliths and the sun and moon cycles was first statistically demonstrated by engineer Archie Thom in 1967 and then in 1984 by archaeoastronomer Clive Ruggles.
However, Dr Higginbottom says the phenomenon is far more widespread than previously realised and highlights a considerable degree of communication between geographically spread communities.
She says the 3-D landscape program developed by Dr Smith has enabled her to achieve extremely high levels of accuracy in her analysis and determine in much greater detail the reasons for the deliberate location of the sites.
"Andrew is a very pedantic kind of person and the software he has developed to look at both the landscape and astronomical orientation together is the best available," says Dr Higginbottom.
Further specialist support is being provided by Emeritus Professor Roger Clay, an astronomer and astrophysicist at the University of Adelaide.
Dr Higginbottom has her own theories on why these early communities went to so much effort.
"These people were living in harsh conditions and had to be very in tune with their environment to survive," she says.
"Whether you are a farmer or hunter gatherer you need to understand the seasons and maintain these cycles for stability and security. It's important to prepare for winter and to know that spring and warmth will follow."
When they have time Dr Higginbottom and her colleagues are hoping to use the 3D landscape model to finally resolve the mystery behind Stonehenge, one of the world's most intriguing and famous stone monuments.
"Stonehenge was definitely used for solar observations but the jury is out on whether it's lunar or solar. I suspect it's both - and our software should be able to confirm it."