Niels Bandholm
Klostervej 30, Kloster - DK6950 Ringkoebing, DENMARK

The Geometric Riddle

The stereographic projection of the Heavenly Sphere used in an astrolabe is a remarkable metaphor for the connection between Heaven and Earth, and as the medieval churches are treasure shrines for this holy union, their placements and proportions are chosen accordingly. Stereographic projection is proposed as the key to the locations of nearly all of the fifteen medieval churches built from 1150 to 1250 on the island of Bornholm in the Baltic Sea. The stereographic projection generates the specific ratio of the square root of 7 divided by the square root of 3 and angles of 33.2° and 56.8°, and leads to a unique astrolabe construction with angles of 40.9° and 10.9°. This ratio and these angles (to the north) are found for nine pairs of distances and half-distances between churches. The high degree of accuracy makes it highly improbable that the arrangement was by chance. Furthermore, some vectors point to pre-Christian holy places: Ertholmene and Ales Stenar in Sweden. The same key has been found in the measure and proportions of pre-Gothic buildings, and in Christian and Celtic iconography.

About the author
This email address is being protected from spambots. You need JavaScript enabled to view it. earned his Master of Science in Chemistry and Physics from Aarhus University, Denmark in 1971, with a M.Sc. thesis in the History of Science in 1972. He is the author of books on chemistry, computer science and energy storage for the Danish upper secondary schools, where he was employed as a teacher and a senior master in physics, chemistry and astronomy from 1966 until his retirement in 2005. In addition, he has organised many conferences on interdisciplinary didactics and teaching. The present study is an example of an interdisciplinary project and was kindly hosted by the History of Science Department (now Department of Science Studies) at Aarhus University 2006-07. He has been greatly interested in environmental issues since 1987, initiating organisations, newsletters and eco-villages. He is now going to build his own dome house in a sustainable society with 250 persons 15 km north of Aarhus.

The correct citation for this paper is:
Niels Bandholm, "The Celestial Key: Heaven Projected on Earth", pp. 95-116 in Nexus VII: Architecture and Mathematics, ed. Kim Williams, Turin: Kim Williams Books, 2008.