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17 April 2014 12:48 pm ,
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Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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Stars Date Egyptian Pyramids
15 November 2000 7:00 pm
By looking at the stars, an Egyptologist claims to have found a new way to date the pyramids of Giza and other ancient sites. According to her calculations, construction on the Great Pyramid started about 75 years later than the currently accepted date. If she's right, Egyptologists may have to rewrite their timelines.
One of the many mysteries of the pyramids is how and why each was built with a precise north-south alignment. The square base of the Great Pyramid of Cheops, for instance, is just 3.4 arcminutes off of true north. That's a precision of about 1 millimeter per meter. Some of the later pyramids, however, deviate more, as if their architects' method for aligning them became less accurate over time.
Suspecting that the heavens might have played a role, Egyptologist Karen Spence of the University of Cambridge, United Kingdom, tested whether two stars called Kochab and Mizar could account for the pyramids' orientation. In the middle of the third millennium B.C., the north celestial pole lay halfway between those two stars--at least in 2467. Before and after that date, a slow shift in Earth's axis skewed the alignment of the two stars with the celestial pole ever so slightly. According to Spence, this drift accounts for the change in pyramid orientation over the years. Using the locations of Kochab and Mizar, she determined the start of construction of the pyramids to within 5 years, she reports in the 16 November issue of Nature.
"Egyptologists are now faced with the challenge of fitting these new dates in their chronologies," says Maarten Raven of the National Museum of Antiquities in Leiden, the Netherlands. He was surprised by the originality of the idea and is "convinced by its simplicity." But he says that more accurate measurements of pyramid orientations are needed to confirm the theory.