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No. 52: Jul-Aug 1987

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Costa rica's neglected stone spheres

Books and articles on Stonehenge, the Easter Island statues, and the Egyptian pyramids are legion. Granted that these structures are important and intriguing, we still ask why Costa Rica's meticulously wrought stone spheres are languishing in the wings of science. They epitomize exquisite workmanship. Such geometric perfection rendered in granite is remarkable-- -for any ancient culture. Lastly, the stones' purpose completely escapes us. Why strew such masterpieces of stoneworking around and even buried under the dark jungle floors?

M.T. Shoemaker also wonders about these things in a nice recapitulation of the stone-sphere mystery. His compilation of facts and figures only impels us to learn more about the spheres and what their shapers had in mind.

  1. The spheres are found on the Diquis River delta, near the Pacific coast of southern Costa Rica.

  2. Stone-sphere sizes range from an inch to 8 feet in diameter.

  3. At least 186 spheres have been recorded in the literature. Surely many more were destroyed and other remain undiscovered.

  4. No local source exists for the granite; and no stone-working tools have been found near the spheres.

  5. "The best spheres are perhaps the finest examples of precision stonecarving in the ancient world." The maximum circumference error in a 6-foot, 7-inch diametre sphere in only 0.5 inch, or 0.2%.

  6. The spheres are often grouped, but no general system or alignment mode seems to exist.

  7. "One very disturbing mystery emerges in examining the Diquis culture. The superb stone-carving skill necessary for the creation of the spheres was not applied to any other object." Why?

Such are the salient facts. To our regret, they tell us little about the How, Why, and perhaps Who of the spheres. (Shoemaker, Michael T.; "Strange Stone Spheres," Pursuit, 19:145, 1986.)

Reference. Costa Rica's stone spheres are covered in greater depth in our handbook: Ancient Man. This book is described here.

Six stone spheres on Farm 4-35C, in Costa Rica
Disposition of six stone spheres on Farm 4-35C, in Costa Rica.

From Science Frontiers #52, JUL-AUG 1987. 1987-2000 William R. Corliss

Science Frontiers Sourcebook Project Reviewed in:


  • "A sourcebook of unexplained phenomena is therefore a valuable addition to a collection of scientific literature. William R. Corliss has provided this in the past with his source books of scientific anomalies in several subjects, and now he has provided it for astronomy. He has done an excellent job of collecting and editing a large amount of material, taken in part from scientific journals and in part from scientific reporting in the popular or semi-scientific press." -- "The Mysterious Universe: A Handbook of Astronomical Anomalies", reviwed by Thomas Gold, Cornell University, in Icarus, vol.41, 1980

  • "An interesting, systematic presentation of unusual weather [..] This book is recommended for a general audience" --"Corliss, William R., Tornados, Dark Days, Anomalous Precipitation, and Related Weather Phenomena, Sourcebook Project, 1983.", revieweed in Choice, September 1983
  • "..the science is necessarily somewhat speculative, but Corliss's symthesis is based on reputable sources." -- "Corliss, William R. (Compiler). Lightning, Auroras, Nocturnal Lights, and Related Luminous Phenomena" reviwed by Joseph M. Moran, Univ. of Wisconsin in Science Books and Films, Sep/Oct 1983

  • "Before opening the book, I set certain standards that a volume which treads into dangerous grounds grounds like this must meet. The author scrupulously met, or even exceeded those standards. Each phenomenon is exhaustively documented, with references to scientific journals [..] and extensive quotations" -- "Book Review: The moon and planets: a catalog of astronomical anomalies", The Sourcebook Project, 1985., Corliss, W. R., Journal of the Royal Astronomical Society of Canada, Vol. 81, no. 1 (1987), p. 24., 02/1987