Neolithic Astronomy in Britain

Perhaps the most mysterious ancient astronomy is that practiced by the neolithic people of Britain and Western Europe. Beginning around 3000 B.C. the people of this region began accumulating giant stones called megaliths and placing them in specific shapes with special orientations. The most famous example of this is Stonehenge, a site on a plain in southern England (see picture below). This monumental feat was begun five thousand years ago, and was continually reconstructed and added on to for two thousand years. The large stones weigh about 30 tons each, and were probably dragged by oxen from a site 20 miles away, while the central volcanic stones come from Wales, over 130 miles away. The astronomical orientations of these stones are generally without question, although archaeoastronomers believe in different levels of the people’s scientific capability. What makes Neolithic astronomy more mysterious is the fact that only the monuments remain; the people had no writing system at that time with which to record their motivations.

At Stonehenge, astronomical alignments are hard to judge because stones were placed next to each other sometimes hundreds of years apart. However, it is commonly accepted that Stonehenge recorded the rising and setting positions of the Sun and Moon at the height of each season. In addition, the oldest stone at the site, called the Heel Stone, was placed at the entry to Stonehenge in such a position that sighting it from the center of the monument points directly to the summer solstice. It has also been suggested that the outer series of holes could have acted as a computer to predict lunar eclipses. This use is the most advanced stage of neolithic astronomy, and is still debated among archaeoastronomers. The picture below shows a schematic of the astronomical orientations at Stonehenge.

Studies of other neolithic sites throughout Britain and France show that many sites have a mathematical significance as well. At the Avebury stone ring, 17 miles north of Stonehenge, the common neolithic unit of distance, called the megalithic yard, is highlighted. The circumferences of the circles of stones are significant: 25 or 50 megalithic yards (a megalithic yard is 2.71 feet). Many of the circles have diameters of 4, 8, 12, 16, or 32 megalithic yards. In an effort to achieve a value of pi which was an integral number, some of the circles are flattened at the top. It is also evident that these people were aware of the geometric relation that we call Pythagorean’s theorem for a right triangle. Several shapes are constructed based on an interweaving of circles and right triangles. Some of the stones could be used as sights to distant mountain ranges, where astronomical events could be pin-pointed.


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Anthony Aveni, Stairways to the Stars, John Wiley & Sons, 1997.

Evan Hadingham, Early Man and the Cosmos, Walker and Company, 1984.

Stonehenge Photo Gallery.

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