Book Review — Marchant, Decoding the Heavens

Marchant, Jo, Decoding the Heavens: A 2,000-Year-Old Computer–and the Century-Long Search to Discover Its Secrets, Da Capo Press, 2009, 328 pp.

Defining the Word “Anachronism”

In the latter half of the nineteenth century, the sponge divers of Greece lived through a technical revolution … the appearance of the diving helmet. After many centuries of free diving to harvest local sponges, the new equipment suddenly allowed access to much more of the Mediterranean sea floor and previously unexploited sponge beds. The industry boomed. Inadvertently, the diving helmet also led to the discovery of a shipwreck off the coast of the small island of Antikythera. Amidst the spectacular bronze and marble statues at the wreck site was a strange lunch box-sized lump, covered in a limestone coating from centuries of immersion and distorted by the effects of decomposition and corrosion. Here and there were visible bits of wood and corroded bronze, faint inscriptions of ancient Greek and what appeared to be thin loops or gears.

Compared to the glamorous artworks it was found with, the “lump” was rather unprepossessing and, indeed, it spent most of the 20th century in obscurity. Not knowing what it was, the curators made little effort to preserve the object, and increasingly, it broke into a more and more fragments in the storage rooms of the Athens’ National Archaeological Museum. The early 20th century descriptions made their way into the hands of a physicist and historian of science named Derek De Solla Price. In the 1950s, he made serious efforts to fully explain what it was, culminating in a 1974 book Gears From the Greeks. And it was partly through his efforts that people as diverse as Arthur C. Clarke, Jacques Cousteau, and Richard Feynman took an interest in the enigmatic archaeological find.

Now, after a century of scholarship and scientific investigation, the humble lump of metal and stone known as the Antikythera mechanism is finally getting its due and we think we know what it is … a geared device, powered by hand, that allowed the successful prediction of solar, lunar, planetary, and eclipse cycles across many decades. It was meant for an educated amateur and came with extensive inscribed instructions on its metal parts. It is the ancient ancestor (in a sense) of the elaborate clocks that were to sweep through western Europe in the 14th and 15th centuries. Except that it was likely built around 100 BC, after what was clearly a long period of earlier experimentation and technical wizardry. What was it doing there? And why does it stand alone amidst classical history without predecessors, companions or contemporary explanation? The mechanism is so unlikely that for many decades it was assumed that it simply could not be from a period in antiquity … or, according to Erich von Daniken, it was left on Earth by aliens. The Antikythera is the ultimate “anachronism” … something that doesn’t seem to belong to its time.

Science writer Jo Marchant provides the first comprehensive book on the device in the last 35 years, a substantial expansion of her 2006 summary article in Nature (In search of lost time, Nature 444, 534-538 (30 November 2006) | doi:10.1038/444534a) which includes the dramatic new discoveries about the mechanism published in 2008. Decoding the Heavens recounts how each generation of archaeologists examined the mechanism and made judgments about what it was and what it did. The story of the men and women who devoted years trying to discover the nature and purpose of the object binds the scientific tale together, often in tragic ways. Science can be a blood sport and the Antikythera brought out the best and worst in many of its students. Our most recent understanding of the mechanism dramatically changes our beliefs about the role of Greek technology in subsequent Muslim and Christian mechanical devices. Hundreds or perhaps thousands of similar devices were subject to damage, loss, and the re-melting of their brass components. The Antikythera mechanism is one-of-a-kind and that, in itself, is a sobering piece of information about the implosion of culture and technology in late antiquity.

In the end, it was the development of non-destructive testing methods (photography, linear X-ray tomography, microfocus computer tomography, polynomial texture mapping ) that finally allowed the most recent generation of scholars and enthusiasts to precisely determine how the device was assembled and operated without irreversibly damaging the fragile remains. Such space-age technology provided an exact means to measure the components, the associated gear teeth and read the faint inscriptions on metal surfaces, even when the metal parts were buried in limestone and largely corroded away. And it was the assembly of an interdisciplinary team of archaeologists, astronomers, artisans, and historians of science that permits some level of confidence in the latest conclusions.

At the margins, the final few details of the operation and function will remain under debate. Did the Antikythera draw upon centuries-long records of Babylonian star-gazing? Was the Antikythera device an astrological tool for elite Greeks and Romans? Was it a functional demonstration of the philosophical orderliness of the universe (especially that of eclipses)? Was this the grand achievement of the final generations of hyper-literate Greek Stoics before Rome dominated the eastern Mediterranean? Where was it made and what relationship did it have to the devices we know were created by Archimedes in Syracuse [Sicily]? Cicero described one as “a sphere that showed the motions of the Sun, Moon and planets around the Earth.” Knowing *what* the device did promises to open up new questions of why elite Greeks wanted to make it.

What is certain is that modern Greeks are immensely proud of the significance of the new discoveries. The Antikythera is slated for its own museum, pulled out of the national museum’s storehouses and given pride of place amongst the gorgeous sculptures and ceramics that typify our idea of ancient Greek culture. It’s clear that the “clockwork” inheritance of Western Europe (so ably outlined in Crosby’s The Measure of Reality — Quantification and Western Society 1250-1600, cb review here) had its roots in the devices first created and elaborated in ancient Greece. And it’s a further sobering addendum to the recent work on Roman archaeology (Ward-Perkins’s The Fall of Rome and the End of Civilization, cb review here) which highlights just how much was lost of the literature, technology, and artisanship of the ancient world. Europe was to wait a thousand years for a reappearance of good roads, effective ceramics and glass, and high levels of literacy. Re-establishing Greek rationality was a halting and initially unsuccessful venture (cf. Tina Stiefel’s The Intellectual Revolution in Twelfth Century Europe, 1985). Devices such as the Antikythera mechanism suggest that even the Roman imperium was a step back, in some areas, from the philosophical and mathematical purposes of the Greeks.

Decoding the Heavens is a straight-forward and well-written account of the history and personalities associated with the examination of the Antikythera mechanism. The author adds atmosphere to the people and places without pitching over into melodrama. One would expect no less from a news editor of Nature. For those with an interest in astronomy, the history of science, or Greek archaeology … this would make an excellent gift, or a fascinating read over several evenings.

One caveat. One personal regret. The story of the discovery and examination of the Antikythera mechanism is so amazing … and it’s significance for ancient history so far-reaching … that we might consider Decoding the Heavens a wonderful foundation for a “teachable moment” in either high schools or universities. A fascinating syllabus or educational module could be created in ancient history, physics or science built around this book and the mechanism itself. The Internet (as evidenced by the Wikipedia article on the device) is awash with enthusiasts and commentators. There are some excellent simulated Antikythera models available in “virtual reality” which really help understand how the moving parts related to each other. It hard to imagine that students wouldn’t warm to the subject with the right introduction.

It’s regrettable that the edition of the book I read is virtually devoid of effective maps and diagrams. Reading the author’s written descriptions of Aegean voyages, astrolabes, astronomical cycles, polynomial texture mapping, pin-and-slot/differential gears, and scholarly dead-ends seemed needlessly challenging. The author is an excellent writer but not all readers start with the same technical background. The set of photographs in the book were welcome but couldn’t replace a more generous graphics budget. A few simple illustrations would make all the difference for a general reader following the failures and successes of the scholars and scientists who examined the mechanism. It’s very unfortunate that the first drawing of the mechanism appears on page 247! A map of Aegean place names mentioned in the book doesn’t seem like a publishing luxury. With Google Maps, I was able to screen capture a workable map while reading but it would have been nice to have one included in the book. Thankfully the end matter … Sources and Further Reading/Index … is very well-done and would support further study if the reader desires. For some reason, the companion website (www.decodingtheheavens.com), which offers a great deal more information of interest, receives little prominence in the book. As mentioned, this is a topic (and book) that begs for interactivity and a substantial role in science education.

The 2006 Antikythera Nature articles were far more fully illustrated and I feel that Decoding the Heavens deserved a bit better in this regard. It’s to be fervently hoped that this gap is corrected in the paperback edition. With better illustrations, spaced strategically throughout the book, this title could be widely recommended for the budding teenage scientist in any house or for the general reader who’s not mechanically or scientifically inclined. This book clearly received a lot of care and attention in the writing. It could be greatly strengthened with equal attention to illustrations and online resources (especially new discoveries in coming years).

Left as is, its natural audience will inevitably be far narrower. Those mechanically or astronomically inclined will find it easy going. All else will struggle at times, and be left to ponder instead the internecine battles between scholars who put forward their own theories on what the Antikythera mechanism was … and what it meant.

Decoding the Heavens is inspiring, thought-provoking, and well done. Those with an interest in ancient history and technology will enjoy it very much.