Mystery of the Giza pyramids’ alignment finally solved by simple shadow trick.
Egyptian pyramids, including the famous Great pyramid of Giza, are so well aligned that it is hard to believe that they were created some 4,500 years ago. How could someone achieve such precision without modern-day technology?
Researchers have hypothesized that the builders might have used the pole star or the Sun, but Glen Dash, an electrical engineer and archaeologist, thinks that the ancient people might have used a relation between Earth’s rotation and the Sun to their advantage.
In a study, published in The Journal of Ancient Egyptian Architecture, Dash notes that each side of the pyramid appears to align perfectly with cardinal points that sit in different directions [north-south-east-west] and form the structure’s square base.
However, there is a small margin of error. The Great Pyramid of Giza is rotated slightly counterclockwise – at 0.067 degrees – from perfect alignment with cardinal points, so is Khafre and the Red Pyramid, according to Newsweek.
Noting this error in all three cases, the engineer has posited that ancient Egyptians might have used the autumnal equinox, when the Sun shines directly on the equator and length of the day and night is nearly equal, to achieve such level of alignment.
Dash told Live Science, on that particular day, the Egyptians might have used a massive pole as a “gnomon” – the tall, projecting piece of a sundial that casts a shadow and shows time.
They would have watched and marked the pole’s shadow move across the sand at regular intervals. This would have taken some time but resulted in a smooth curve, on which two points would have formed a perfectly straight line running east to west.
The idea not only seems feasible but has also been tested by Dash, with a very similar margin of error that has been noted in the Giza pyramids. However, there is still no evidence to confirm if this was their way or something else.
“The Egyptians, unfortunately, left us few clues,” Dash wrote in the paper. “No engineering documents or architectural plans have been found that give technical explanations demonstrating how the ancient Egyptians aligned any of their temples or pyramids”.