Stonehenge

Stonehenge, a prehistoric stone monument in southern England, has strangely beautiful shapes and a rough symmetry. Above all, it is a mystery that has made Stonehenge an attraction and held fascination for centuries. Our Stonehenge show starts with the ideas of Gerald Hawkins, a young astronomer, who boasted in 1963 that he had “decoded” Stonehenge, and that it was an astronomical observatory and an eclipse calculator. The debate over the more speculative of Hawkins’ claims has still not ended, but his basic ideas have convinced most scholars that astronomy did indeed play a more important role in the design of Stonehenge than had been suspected, and has helped to stimulate a whole generation of investigators known as “archaeoastronomers.” This planetarium program, designed for public audiences and for students in grades 4 and above, aims to communicate important aspects of how science works and how new ideas are invented, explored, refined, and tested at ancient structures around the world.

by Alan J. Friedman

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Contents

Preface
Objectives
Materials
Media
Setup
Script
Discover More
Acknowledgements

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Preface

    Stonehenge, a prehistoric stone monument in southern England, is one of the best known structures in the world. Its strangely beautiful shapes, rough symmetry, and above all its mystery have made it an attraction and fascination for centuries. Articles, pamphlets, scholarly books, and novels have been written about it. Its silhouette has appeared on the covers of travel guides, rock music albums, freshman astronomy textbooks, and religious tracts.

    Interest in Stonehenge among scholars intensified dramatically in the past few decades as archaeologists have made major strides in learning about the neolithic (new stone age) and bronze age people who lived in England at the time Stonehenge was built. The public became entranced by the ideas of Gerald Hawkins, a young astronomer, who boasted in 1963 that he had “decoded” Stonehenge, and that it was an astronomical observatory and eclipse predictor. The debate over the more speculative of Hawkins’ claims has still not ended, but his basic ideas have convinced most scholars that astronomy did indeed play a more important role in the design of Stonehenge than had been suspected. The excitement also helped to stimulate a whole generation of investigators who are studying the new science of “archaeoastronomy,” and who have learned much about the importance of astronomy to ancient peoples around the world.

    This planetarium program seeks to take advantage of the continuing fascination with Stonehenge, and the dramatic story of Hawkins’ hypothesis, to communicate to students important aspects of how science works. New ideas about Stonehenge were invented, explored, refined, and tested at other ancient structures around the world. Some of these sites, particularly in the Americas, turned out to have astronomical alignments far more accurate and indisputable than does Stonehenge itself.

    Thus the Stonehenge story is an excellent example of the human drama of science, with all its inspiration, mistakes, controversy, and, in the end, immense satisfaction in having glimpsed a little more of how the universe works.

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Objectives

In this planetarium program, students will be able to:

1. Describe the appearance, age, and long-standing puzzles about the purpose of Stonehenge.
2. Explain the origins and basic components of Gerald Hawkins’ hypothesis that Stonehenge could have been used as a naked-eye observatory for horizon astronomy.
3. Perform an investigation, using the planetarium, to test Hawkins’ hypothesis through the search for possible horizon alignments.
4. Describe, qualitatively, the pattern of the Sun’s horizon position at rising and setting throughout the year, and the relation of the Sun’s apparent motion to the seasons.
5. Describe how Hawkins’ ideas were applied to other sites.
6. Increase their estimation of the intelligence, ingenuity, and dedication of ancient peoples.

Note: This program, with only minor adjustments, has been used extensively with audiences from 3rd grade through adult.

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Materials

If certain digital effects are already available in your fulldome digital system, you should use the software platform’s digital effects wherever possible. Still images in the script for those instances provide examples of what to show audiences. 

The key activity in this program involves searching for horizon events, and then comparing those events with alignments of the stones at Stonehenge. Two basic tools are needed: horizon markers, which students use to record rising and setting locations on the horizon, and indicators for the alignments Hawkins found at Stonehenge.

Get horizon graphics (.zip file) for showing the alignment archways.

Or see PDF document of ideas for simple projectors to show Stonehenge horizon archway alignments:
Version I: A Cardboard-drum Silhouette Projector
Version II: A Photocopy Mini-silhouette Projector
or
Cardboard Archways Attached to the Dome

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Media

Download all media for Stonehenge & horizon trilithon position images

*Media Credits
Akajune: Wikipedia contributor, http://commons.wikimedia.org/wiki/File:Heelstone.JPG
Brennan: Matthew Brennan, Wikipedia contributor, http://en.wikipedia.org/wiki/File:Stonehenge_from_the_northeast.jpg
Friedman: Alan J. Friedman.
Holt: the Holt Planetarium, after Hawkins. Berkeley, CA
Krupp: E.C. Krupp.
Sorrell: Alan Sorrell, Her Majesty’s Stationery Office

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Setup

1. Precession, if available, set at approximately minus 3600 years (the last major phase of Stonehenge was completed about 1550 BC).
2. Latitude set at 51 degrees north.
3. Check for correct alignments of the Stonehenge archway indicators with sunrise and sunset on the solstices.
4. Annual motion set to today’s date (if you happen to be close to either of the solstices, you might want to select another date).
5. Diurnal motion set for shortly before sunrise.
6. Cue first visual.
7. Sun, Moon, and atmosphere on.
8. Planets on unless one or more by coincidence happen to be at the same position as a solstice Sun, in which case they should be left off.
9. Stonehenge alignment indicators off.

DIGITAL EFFECT: Setup
Load all media needed for the program. Set up the sky for the beginning of the program, using “today” and 2 hours before sunset, at Stonehenge’s coordinates.

Note: The summer and winter solstices occur on, or within one day, of June 21 and December 21 respectively. As noted earlier, the actual date can vary by a day or so from year to year because our calendar does not track the motion of the Earth around the Sun exactly. Most small planetariums do not show these variations and the extreme risings and settings always occur on June 21 and December 21. The actual date of the winter solstice 3500 years ago was ~June 2. For convenience, the presenter should just say “winter solstice” and the actual date is optional information.

DIGITAL EFFECT: Use UTC
Set the time zone to Universal Time (UTC). This makes using the planetarium clock easier to understand, so it shows Stonehenge’s local time rather than the user’s local time.

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Planetarium Show Script

• Introduction: Stonehenge
• Gerald Hawkins, Astronomer and Tourist, Makes a Guess
• Predicting Today’s Sunset
• Reconstructing Stonehenge
• Marking More Risings and Settings
• Tracking the Migration of Sunset
• Hawkins’ Conclusion

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Discover More About Stonehenge

Anthony F. Aveni, “Archaeoastronomy: Past, Present, and Future,” Sky and Telescope, November 1986, 456-460. A fine summary of the growth and recent activity of the field. Aveni is an expert on archaeoastronomy of Mesoamerica and Peru, and has many books and articles on western hemisphere sites.

Aubry Burl, The Stone Circles of the British Isles, Yale University Press, 1977. This is the basic book for stone circle fanciers. It has a complete bibliography, descriptions of essentially all the circles, and an excellent introduction to archaeological research. Burl presents all the theories evenhandedly. See also Burl’s book on a favorite circle—Prehistoric Avebury, Yale University Press, 1979.

D. V. Clarke, T. G. Cowie, & Andrew Foxon, Symbols of Power at the Time of Stonehenge, Her Majesty’s Stationery Office, 1985. This lavishly illustrated book, originally the catalog for an exhibition, pays little attention to archaeoastronomy but provides a wealth of information on the people in Britain at the time when Stonehenge was being built. Beautiful color photographs show archaeological finds. (The dates given for Stonehenge in this book do not use the recently corrected radiocarbon dates, which place Stonehenge several hundred years earlier.)

Gerald Hawkins, Stonehenge Decoded (in collaboration with John B. White), Doubleday, 1965; and Beyond Stonehenge, Harper & Row, 1973. Personal accounts of Hawkins’ work. The astronomical explanations are good, and in Stonehenge Decoded the excitement is high. Hawkins does not do justice to Alexander Thom’s work in either book. 

Fred Hoyle, On Stonehenge, W. H. Freeman, 1977. The best presentation of the astronomy of archaeological work. Hoyle’s interpolation theory of Stonehenge astronomy is underrated by the archaeologists (see MacKie, below), but is novel and plausible. His speculations beyond the physical evidence are interesting but very elaborate.

E. C. Krupp, In Search of Ancient Astronomies, Doubleday, 1977, and Echoes of the Ancient Skies, Harper & Row, New York, 1983. The earlier book contains essays by several of the most important researchers covering work around the world. Krupp’s own summary of Stonehenge astronomy is the best concise review of this work. Echoes provides a solid and entertaining review of many aspects of modern archaeoastronomy, including much new material on American sites and an extensive bibliography.

Euan Mackie, Science and Society in Prehistoric Britain, Elek, London, 1977. MacKie reviews basic knowledge about stone circles and British pre-history, with special emphasis on the work of Alexander Thom. MacKie presents a good case for Thom, and draws analogies and further inferences about Thom’s work. The astronomy and statistics are not confidently presented, and the work by Hoyle is passed over too quickly and sarcastically.

Jeremy Sabloff, ed., Archaeology: Myth and Reality, W. H. Freeman, 1982. A range of opinions on controversial issues in archaeology, including astronomical interpretations. Includes an article by Glyn Daniel, who does not accept any conclusions of the Hawkins or Thom ideas.

“Archaeoastronomy,” The Bulletin of The Center for Archaeoastronomy. A journal of review and discussions published by The Center for Archaeoastronomy, University of Maryland, College Park, MD 20742.

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Acknowledgements

    Programs involving Stonehenge are a staple of planetariums around the world, especially since the publicity surrounding Gerald Hawkins’ 1965 book, Stonehenge Decoded. Alan Friedman wrote the original version of this Stonehenge program in 1972 for use as the opening program in the William K. Holt Planetarium at the Lawrence Hall of Science, University of California, Berkeley. As far as we know, this was the first participatory program inviting visitors to share the excitement of Hawkins’ theory. 

   The idea for a participatory, activity-based program on Stonehenge was inspired by a horizon-marking planetarium lesson Friedman saw given by Bob Andress in the Warrensville Heights school planetarium in Ohio. The first trial of the key Stonehenge activity was made with the help of Mr. Andress and his students.

    This activity-based program has been adapted, improved, and performed at the Holt Planetarium and many other planetariums for the past twenty years. We are grateful for comments and suggestions received over these years from many students, planetarians, and scholars. We would particularly like to thank Dr. George Reed, West Chester State College, for his encouragement, and the participants in the Summer 1992 Astronomy and Space Sciences workshop in Berkeley for their critiques.

    Dr. Edwin C. Krupp, Director of the Griffith Observatory and Planetarium, and a distinguished authority on archaeoastronomy, kindly read and commented on this latest revision of the original Stonehenge activity-based program. Alan Gould developed the activities and special effects, and Dr. Joseph Snider provided the Solar Motion Demonstrator activity. The responsibility for any inaccuracies is mine. Edition 2009 was revised by Alan Gould and Toshi Komatsu. Thanks to Angela Miller for adaptations of the script for access through the internet.

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