Friday 17 November, 2000
The Stargazers of Ancient Egypt
The Great Pyramid of Giza, among the seven wonders of the ancient world, points towards the celestial north pole with a margin of error of only a tiny fraction of one degree.
Now Dr. Kate Spence, a British Egyptologist, believes she may have solved two of the great mysteries of archaeology - how the ancient Egyptians aligned the pyramid with such remarkable geographical accuracy and when the vast royal tomb was built.
John Duce reports for Science in Action.
Pointing north
The Great Pyramid is a master of precision. Comprised of an estimated 2.5 million limestone blocks, archaeologists have known for over a century that the Great Pyramid was pointed almost exactly north, but nobody has been able to explain how the ancient Egyptians managed to align it with such unprecedented accuracy.
The deviation in accuracy is minute as Dr. Spence explains:
‘The Great Pyramid is extremely accurately aligned towards north. The sides deviate from true north by less than three ark minutes, that’s less than a twentieth of a degree, which is extremely accurate in terms of orientation.’
Modern astronomers would have little difficulty in finding north because the Pole Star, Polaris, is almost directly above the North Pole. But astronomers know that the Earth regularly wobbles very slowly on its axis over a period of 26,000 years and so in ancient Egyptian times there would have been no star overhead marking true north.
The Spence theory
Using computer simulations of the night sky as it would have been seen at the time of the Egyptians, Dr Spence, from Cambridge University, suggests that the ancient Egyptians carefully monitored two stars which revolve in the northern region of the night sky.
The north-finding stars were Kochab, in the bowl of the Little Dipper (Ursa Minor), and Mizar, in the middle of the handle of The Plough or Big Dipper (Ursa Major). Dr Spence says that the ancient Egyptians realised that when one was directly above the other then the line between the two-marked true north.
Dr Spence speculates that these astronomical calculations were made at special ceremonies early in a pharaoh's reign and that construction work would then begin on the pyramids to house their tombs. She explains:
'What would probably have happened is that the king would have dressed in his ceremonial gear, and there would probably have been priests dressed as gods who would begin stretching chords and marking out the base. It would have been a highly charged religious atmosphere, taking place in the dark, at night, with torches everywhere. It would have been a spectacular ceremony.'
The ancient Egyptians fascination with the night sky is well known. Believing that the Gods lived in the Duat, an afterworld in the sky, the pharoahs who were responsible for the construction of the pyramid at Giza, would have associated the stars with eternity and afterlife.
Dating the pyramids
In the past the date of the ancient Egyptian pyramids has been a source of much debate among historians, who have put it at around the middle of the third millennium BC, by tracing the chronology of Kings. However, publishing her research in the scientific journal Nature, Dr Spence says her theory gives a more precise date for the beginning of construction work on the Great Pyramid.
The celestial north pole was only aligned exactly with Kochab and Mizar in 2, 467 BC, which would put the beginning of building work about 70 years later than many archaeologists, have previously thought.
Dr Owen Gingerich, Senior Astronomer, at the Harvard-Smithsonian Centre for Astrophysics said Dr Spence's theory is an ingenious and convincing astronomical solution to a long-standing mystery. He comments:
‘I was rather tickled to see the solution that she had put forward and wondered why nobody else had thought of it before, because I think it makes a lot of sense and it has an internal coherence.’
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| The Seven Wonders of the World |
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The list of the seven wonders of the world has been adapted over time and has encompassed both the natural and the modern world. However the original list of the seven wonders of the ancient world was compiled around second century BC and read as follows:
The Great Pyramid of Giza
The Hanging Gardens of Babylon
The Statue of Zeus at Olympia
The Temple of Artemis at Ephesus
The Mausoleum at Halicarnassus
The Colossus of Rhodes
The Lighthouse of Alexandria |
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Nature |
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Sacred Sites |
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