The pyramids of Giza have long puzzled researchers. From the mysterious chambers hidden inside to exactly how these ancient structures were built, so many questions have yet to be answered. As for the perfect alignment of the three pyramids, an experiment involving the autumnal equinox might be able to offer a plausible explanation.
The Great Pyramid of Giza was built almost perfectly - with only a very slight counterclockwise error - along the cardinal points: north, south, east, and west. "The builders of the Great Pyramid of Khufu aligned the great monument to the cardinal points with an accuracy of better than four minutes of arc, or one-fifteenth of one degree," explained archaeologist and engineer Glen Dash, author of the study. What's even more fascinating is that this precision was achieved by the ancient Egyptians without the use of modern technology. Several theories have emerged about how they did this - including using the pole star or the Sun's shadow - but the explanations remained ambiguous...
That is, until Dash's experiment offered a new explanation. He began tracking the points of the shadow cast by a gnomon at regular intervals, beginning on the first day of the fall equinox. At the end of the day, the moving shadow formed a curve of recorded points, and Dash then used a string attached to the gnomon to draw a perfect circle around it. The circle intercepted the curve formed by the shadows at two points, through which he then drew a straight line, running almost perfectly from east to west, with the same manner of error as the three pyramids.
Dash recorded the observation in the study writing, "On the equinox, the surveyor will find that the tip of the shadow runs in a straight line and nearly perfectly east-west." Although the experiment's results matched the phenomenon found in the pyramids, we can't be certain it's the method that the ancient civilization used. "The Egyptians, unfortunately, left us few clues. 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," wrote Dash in the study, published in The Journal of Ancient Egyptian Architecture. We have yet to determine whether the autumnal equinox is really the answer to the pyramids' fascinating alignment. But we can't deny Dash's experiment brought us a lot closer to solving one of the many mysteries of these structures.