History & Culture
Annals of Astronomy:
The Hottest Topic is Ancient Astronomy
Two astroarchaeology sites are the focus of recent research and news.
By Dr. Clifford J. Cunningham
Till Credner/IAU OAE
Stonehenge is an ancient stone monument in the English countryside.
[Photo by Samuel Wölfl/Pexels]
The most fashionable aspect of the history of astronomy in 2024 is from ancient times. With discoveries from two sites, these old, cold stones have become the hottest topic.
First, the Stonehenge site. After centuries of examination and decades of scientific study, the origins of Stonehenge revealed such a surprise in August it even made the news on television. There is a six-ton stone there, known as the Altar Stone. It is a greenish sandstone block measuring 16 by 3 feet (5 by 1 meters), and rests at the center of the famous stone circle. Even many visitors to Stonehenge don’t notice it because it lies flat and is partially buried under two other fallen stones.
Archeoastronomers have known for a long time that the builders of Stonehenge hauled the upright stones that form the circle from a location in southeast Wales known as Brecon Beacons, and they thought the altar stone was also from there. But Dr. Richard Bevins at Aberystwyth University in Wales suspected otherwise. In 2023, he published a preliminary study of the stone; this was followed up by a definitive paper in the journal Nature in August 2024, in which he and his colleagues proved a non-Welsh origin for the Altar Stone.
The Altar Stone sits underneath two sarsen stones, also referred to as silicified sandstone blocks.
[Professor Nick Pearce, Aberystwyth University]
Great Britain consists of three nations: English, Welsh, and Scottish. Those north of the English border can now proudly lay claim to the Altar Stone. By studying mineral grains in the stone, Bevins and lead author Anthony Clarke (Curtin’s School of Earth and Planetary Sciences) proved the stone formed between 1 and 2 billion years ago and is from the Orcadian Basin in Scotland. How could such a huge rock have been transported 466 miles (750 kilometers) with the means available around 2600 BCE?
The most likely route appears to have been by sea, which means the high level of organization required far exceeds any of our current understanding of what people of that era had at their command. The whole idea of long-distance trade networks now needs to be incorporated in our theories about Stonehenge, which appears to have been an island-wide effort of astonishing complexity.
Astronomical work is ongoing at Stonehenge this year and into 2025, to study the alignment of the stones with the Moon at the so-called lunar standstill, where the Moon rises at the most extreme southerly point every 18.6 years. Instead of being a monument to align with the Sun, it is increasingly obvious that the earliest use of Stonehenge, before the great Circle was erected, was dedicated to the Moon’s position in the sky.
Göbekli Tepe, which dates to about 12,000 years ago, sits in southern Turkey. Some researchers think this ancient site might be the world's first calendar with engravings counting 365 days.
[TaylanOzgurUksal/Wikimedia CC BY-SA 4.0]
Some researchers think the marks on this pillar at Göbekli Tepe represent an ancient calendar.
[Martin Sweatman]
The second site that is finally revealing its secrets is 6,000 years older than Stonehenge: Göbekli Tepe in southern Turkey, near the border with Syria. It consists of great stone rings, one of them 65 feet (20m) across; in comparison, the great trilithons at Stonehenge make a circle 45 feet (14m) across, while the outer ring of smaller stones are 100 feet (30m) in diameter. Archaeologists who work at the Turkish site have dubbed it humanity’s first cathedral on a hill.
Research released in the journal Time and Mind in August 2024 has revealed Göbekli Tepe to be the world’s oldest calendar, with a combination of the Sun’s position and the Moon’s phases: a lunisolar calendar. Perhaps fittingly, the researcher who made this discovery is from Scotland, at the University of Edinburgh.
Martin B. Sweatman studied V-shape symbols carved into the pillars, finding one with exactly 365 V’s on it: the number of days in a year. To add further credence to this interpretation, the summer solstice was denoted with a special V, worn around the neck of a bird-like creature that was used in other places nearby and at this site to represent the summer solstice. The carvings also track cycles of the Moon and the Sun.
Sweatman said in a news release, “It appears the inhabitants of Göbekli Tepe were keen observers of the sky, which is to be expected given their world had been devastated by a comet strike. The event might have triggered civilization by initiating a new religion and by motivating developments in agriculture to cope with the cold climate.”
DR. CLIFFORD J CUNNINGHAM is a historian of astronomy. In the summer of 2024 he was in the Middle East, visiting ancient archeological sites in Jordan, Egypt, and Cyprus.
A comet strike? Yes, in a more extraordinary astronomical connection, many archaeologists now accept that a comet hit the region around 10850 BCE, triggering a mini-ice age. A pillar at Göbekli Tepe appears to depict the Taurid meteor stream lasting 27 days, which may have been the source of the devastating comet impact. It also seems the temple carvings chart the movement of the constellations across the sky based on the time of year, making Göbekli Tepe the world’s first celestial calendar. ✰
(Published September 4, 2024)
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