THE ANCHOR OF THE WORLD (cont)
Did the Pyramid Builders of the Old Kingdom use the Pole of the Ecliptic?

By Robert G. Bauval

THE SLOPE OF THE PYRAMIDS

It is well known that the monumental Pyramids of the Old Kingdom in Egypt, from the 4^th Dynasty (c. 2500 BC) to the 6^th Dynasty (c.2100 BC), have slopes 52° +- 2°, with two notable exceptions being the two pyramids at Dashur, with the Red Pyramid having a slope of about 43° 22' and the Bent Pyramid having half its height at slope of 54° 27' and the top half at 43° 22'. Today there are still some 25 royal pyramids standing in the 25 kilometres strip of desert land adjacent to the west bank of the Nile Valley near modern Cairo. Most have their core masonry sufficiently intact to allow relatively accurate measurements of their slopes. A recent batch of slope measurements were provided by Jaromir Malek and John Baines in 1984 and Mark Lehner in 1997, of which 17 pyramids spanning from the 4^th to the 6^th Dynasties can by analysed. The first, a pyramid attributed to the relatively unknown pharaoh Huni of the 3^rd Dynasty, is generally thought to have been 'converted' into a true, smooth-sloped pyramid by the founder of the 4^th Dynasty, king Snefru, the father of the Khufu builder of the Great Pyramid at Giza. I have thus considered the Meidum pyramid as being part of the 4^th Dynasty trend.

No convincing explanation has, so far, been given as to why the Pyramid builders selected slopes of 52° +/- 2°. There are geometrical theories and also construction issues that have been proposed as an explanation in recent years, but none are very satisfactory. From table 1 we can see that the angle of slope most often encountered is 53° 07' 48", which occurs in nearly 50% of the Old Kingdom pyramids. This range of angles, from 54.5° to 51.7°, as can be seen from Table 1 above, bears a conspicuous correlation to the range of angles of the pole of the ecliptic of 54.5° to 51.5° at upper culmination as seen from across the pyramid fields of the Old Kingdom. In consideration of this, it is very tempting to inquire whether the ancient builders could have incorporated the angle of the pole of the ecliptic in their design of pyramids.

Let us examine this possibility.