Archaeoastronomy knits together the celestial lore, mythology, religious beliefs, cosmology, archaeology and the astronomical practices of the ancients. Throughout the world, ancient cultures left behind ruins and monuments which reflected their astronomical studies.
The Anthropology of Astronomy
The Great Pyramid at Giza in Egypt, the Mayan ruins in Mexico, the Nazca Lines in Peru and the structures at Chaco Canyon in the American Southwest are just a few monuments left by ancient peoples as they studied the workings of the heavens. Archaeoastronomy is the anthropology of ancient astronomy. The more recent work by Galileo, Kepler, Copernicus and Newton, among others is more accurately classified as the modern history of astronomy.
Midsummer Morning at Stonehenge
In the 17th century the British scholar, William Stukely observed that the horseshoe configuration of 19 Bluestones and the Trilithons opened in the direction of the midsummer sunrise. He suggested that the Stonehenge builders deliberately laid out the monument in anticipation of the summer solstice. The sun rises directly over the Heel Stone and the first morning sunbeams shines directly into the center of the monument between the open arms of the horseshoe array. The discovery indicated that Stonehenge might have been a site for sun worship and concluded that the builders constructed it as a temple to the sun.
An Astronomical Calendar
More recently astronomers discovered that in addition to its functions as a sun temple, Stonehenge served as an astronomical calendar. It is aligned with the solar and lunar cycles and can be used to predict eclipses as well. Researchers have shown that the other stone rings throughout Britain are also oriented toward the sun and moon.
An Astronomical Calculator
Its Neolithic builders must have had some precise astronomical knowledge of the orbits of the sun and moon in order to build an astronomical calculator. It is known that construction began on Stonehenge about 5000 years ago and went through an estimated five phases before it was completed. Archaeologists arrived at the construction date because the digging instruments were deer antlers which were among the relics found at the site. Radio-carbon dating techniques revealed the age to be about 5000 years. About 1500 years ago the site fell into disrepair and was never used again.
The original builders of Stonehenge did not set the site up as an astronomical calendar when they first began building it. Archaeologists theorize that the Bluestones and the Trilithons were not placed in the site until 2000-2500 years after the original construction. At some point, the builders dug out 56 holes and set the Aubrey Stones in a circular configuration inside the site. They also placed four Station Stones to mark the corners of a rectangle in the center of the site. They are referenced to the Heel Stone which is located outside the circular configuration.
The Aubrey Stones
The Aubrey Stones served as reference points along the circumference of the circle. They were essential in tracking the moon and sun cycles. The moon’s cycle takes 27.3 days. The ancient astronomers moved markers along these stones two at a time to indicate the moon’s progress through its monthly orbit. They also marked the solar progression on an 18.7 year circuit around the stones and they moved the markers along three at a time on this cycle. This allowed the astronomers to mark the points of intercession these two cycles. These intersection points are the nodes which allowed the astronomers to predict future eclipses of the sun and moon.
Keepers of the Star Lore
In most ancient civilizations where solar and lunar calendars were developed, the priestly class alone knew the secrets of the stars. This knowledge set them apart from their peers and gave them respect and power. The priests also kept the planting calendar and reported the best times for planting in the spring and when the frosts would begin in the fall.
The priests were a privileged class set apart from the rest of the community and they guarded their arcane knowledge carefully. If a sacrifice was necessary to keep the moon in orbit or for the seasonal cycles to continue, the priests announced the news to the community and directed that ritual themselves. Some considered the priests to be more important that the tribal leaders because they were the ones responsible for keeping the gears of the universe well oiled and in working order.
Sources:
Stonehenge by Rosemary Hill; Harvard University Press, 2008
Stonehenge: Ancient Temple of Britain by Robin Heath, Walker & Company, New York, 2002
Diane Evans - I am a retired civil engineer as well as a member of Sisters in Crime and the Society of Children's Book Writers and Illustrators.
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