The Archimedes Palimpsest

The “Jurassic Park” of Manuscripts
By Davide Castelvecchi

X-rays can see past the gold painting by a 20th century forger to Archimedes’ text beneath. (Credit: Will Noel, Walters Art Museum)

A physicist is using a baseball-field-sized particle accelerator as a scanner to read the lost pages of a medieval manuscript containing the works of Archimedes.

This is a 4 1/2 minute radio piece I did for the May 22, 2005 Are We Alone?, a radio show produced by the SETI institute (yes, the ones of the movie Contact).

Download the mp3 file (high quality, 4.13 Megabytes).

Download the entire show from the SETI Web page (12.5 Megabytes). My piece opens the show. This version includes the host’s introduction (Seth Shostak is the host), but one of the interview soundbites has been cut.

Update August 2006: two new rounds of X-ray scans have revealed new details of the manuscript — see my August 3 piece in National Geographic News.

Full Transcript:

Host’s intro: Particle accelerators are often compared to time machines: You know, physicists will use these behemoths in experiments that recreate the conditions in the big bang. Of course, that takes us back about 14 billion years. But accelerators can also help us travel to somewhat more recent history. For the American Physical Society, here’s Davide Castelvecchi [DAH-vee-deh kas-tell-VECK-key] on how high-energy particles can shed light on one of the most famous thinkers of ancient Greece.

Until he died in 212 B.C. at the hands of the Roman invaders, Archimedes was perhaps the smartest man on the planet. He had unprecedented insights in science, technology and math. And this Greek Sicilian was, of course, the man who had the original “Eureka” moment.

According to legend, Archimedes was taking a bath one day, when he suddenly understood the physics principle of why his body floated in water. He got so excited that he ran butt naked down the streets, screaming “Eureka!,” which is Greek for “I’ve found it!”

But even Archimedes could have never imagined the 21 st century tools people would use to understand his work.

For 100 years now, historians have been puzzling out a manuscript called the Archimedes Palimpsest. The Palimpsest is a copy of Archimedes’ works made by Greek monks around 900 A.D. Without it, some of those works would have been lost for ever.

Uwe Bergmann, a physicist at the Stanford Synchrotron Radiation Lab, in California, is now helping historians read the Palimpsest through computer imaging — just like scanning old photos. But his scanner is a donut-shaped particle accelerator the size of a baseball field.

The accelerator produces powerful beams of X-rays. Bergmann can point a beam as thin as a human hair to scan the tiniest details of the manuscript, searching for traces of iron.

[Bergmann] “We are interested in finding all the iron because the text was written with an iron-based ink.”

Why do you need X-rays?

That’s because around 1100 A.D., the manuscript was “palimpsested.” That means the pages were erased and reused to make a new book.

[Noel] “It was taken apart, the leaves were scraped off, they were stuck in a random corner together with leaves from other books.”

Will Noel, of the Walters Art Museum in Baltimore, is the caretaker of the Palimpsest.

[Noel] “And later on, a scribe came and wrote over them at 90 degrees to the Archimedes text, and reconstituted it as a prayer book.”

But traces of Archimedes’ words did survive underneath the prayer text. A historian noticed them in 1907, unveiling a text called the Method of Mechanical Theorems. In the Method, Archimedes showed that he understood concepts in physics and math that would not be rediscovered until the arrival of Isaac Newton, almost two thousand years later.

But by World War I, the manuscript had mysteriously disappeared. It showed up again in New York at an auction in 1998. An anonymous collector bought it for 2 million dollars, and later he left it in Will Noel’s custody at the Walters Museum.

Since then, scientists and historians from around the world have volunteered to help read more of the Palimpsest. But still, about one-third of the manuscript has been unreadable. Parts are just too faint; parts have been damaged by mold. And sometime in the 20 th century, forgers covered four whole pages with gold, and painted fake medieval miniatures on it.

But X-rays can see through gold and mold, and they can spot even microscopic traces of leftover ink, making a digital image of the lost text.

[Noel] “What you can potentially do is to recreate a page of the palimpsest as it was before it was even palimpsested. That’s the Jurassic Park of manuscripts. And that’s a very cool idea. That’s a very cool idea. And we’re working at it.”

Earlier this month, Uwe Bergmann tested his X-ray technique on a gold-covered page. The words of Archimedes came back to life.

[Bergmann] “It is just absolutely stunning that all of a sudden you see that there is text underneath, and there was no way to see it before. We could hardly believe our eyes.”

Even before this first test was completed, historians were already at work, deciphering the rediscovered text.

Bergmann says he is still improving his technique, and he might soon be able to read dozens more new pages. More Eureka moments might be coming up.

For the American Physical Society in Washington, I am Davide Castelvecchi.

Copyright © 2005, SETI Institute

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