Working in a biomechanics lab really gets me wondering how things are built. Lately, I’ve been wondering just what do we know about how the Egyptian pyramids were built 4,500 years ago. My pondering has brought me to some pretty interesting stuff.
First, of all, I had no idea exactly how huge the Egyptian pyramids are. Each pyramid used something like 2 million stones that were up to 15 tons each! The biggest (and oldest) of the three pyramids, The Great Pyramid, is 481 ft (147 m) tall, about the same size as the Space Needle in Seattle. Compared to modern skyscrapers, that’s not much, but consider trying to build anything on that scale without cranes, impact drills, hydraulic lifts, or, frankly, any complex machinery. The feat becomes much more impressive, doesn’t it? So how’d they do it?
Another fascinating point is their astronomical alignments. Each pyramid is built with their four corners pointing in the cardinal directions, with the Great Pyramid’s north-south accuracy within 1/15 of a degree! The astronomical link of the pyramids requires us to consider how the night sky looked way back, around 2480 BC. A recent study has shown that the pyramids’ alignment to true north is accurate to 3/16’s a degree. To underline the remarkable feat of this accuracy, the Meridian Building in London, also built on a north-south line in the 1960s, is accurate to only 9/16’s!
Though contested, it is thought the points of the pyramids are aligned with three stars in the belt of Orion. Given the position of Earth’s orbit, and the difference in the night sky, it is contested that Orion didn’t exist in quite the orientation we recognize today, and Egyptians recognized the stars in the Orion belt (Alnitak, Alnilam, and Mintaka), but not Orion as a whole constellation. Intended or not, the alignment is remarkable.
How the heck did they achieve such accuracy, let alone building such massive structures with, presumably, best access to simple machines? Here’s the thing: no one really knows. There are loads of theories floating about, though. For example, many archeologists think that Pharaoh Khufu (the fine fellow who commissioned the pyramids) may have used the fall solstice to determine the east-west path of the sun. Others posit that the ancient African architects used alignment of certain stars (Mizar of the Big Dipper and Kochab of the Little Dipper) at night, using a tool called merkhet, to determine the direction of north.
As for the physical construction, a common hypothesis is that the Egyptians used ramps. Each of the pyramids are at the same elevation, and line up neatly with the slope of the plateau on which they’re built. The consistency between all the buildings, and their placement in the plateau support the hypothesis that ramps were used in construction. However, no physical evidence, or engineering plans have been found.
We do know that the stones, quarried from 500 mi (805 km) away, were brought to the plateau using temporary canals and boats. We also know that the pyramids were build with human labor. Contrary to popular thought, evidence suggests the pyramids were not built with slave labor, but rather a rally of the people of all social classes coming together to construct the ancient marvel. Archaeological digs have unearthed a nearby city that clearly show the builders were well-fed, well-organized, and centrally led.
It certainly seems, as we continue to learn about the oldest Ancient Wonder of the World, that we’re going to unearth more questions…possibly more than answers! I know such a thing may be anticlimactic at first glance, but in the age of human knowledge existing at our fingertips, finding unanswerable questions is a special occurrence indeed!
More reading!
Pyramids of Giza
Astronomical alignment
More astronomical alignment
Cardinal alignment
The Curious Dr. Z 