Tuesday, December 12, 2006

Ancient Smarts

Genius defies all anticipation. ~ Henri Bergson

One of the hallmarks of modern civilization is a remarkable smugness because of our technological advancement. For decades, the conventional wisdom was that the ancients were clever enough, but the real genius of mankind was to be found in the modern age. Over the last twenty years or so, we had to come to grips with the fact that early civilizations were a damn sight more advanced than we've credited them.

We have found that many of Da Vinci's clever designs actually work. Ironically, when we have trouble making them work, it's because our modern engineers try to “improve” them; when we follow Leonardo faithfully, the results are often remarkable. The more we investigate the engineering of the Romans, the more impressed we become with the sophistication and organization with which they were able to work.

And then there's the lump of bronze found off the island of Antikythera.

The Antikythera Mechanism, or, as it's familiarly known, the Antikytherum, was found in 1902 by sponge divers who were exploring a wreck. It was a lump of corroded bronze that was first thought to be part of a statue, but a closer examination showed that there was more to this lump than first met the eye.

There were gears, gears with v-shaped teeth. And that was totally unexpected.

The Antikythera Mechanism was dated to around 150 BC. There were known to be geared mechanisms dating to that time, but all of them had square gear teeth, which are easier to make. In fact, there were those who felt that there was not sufficient technology available at the time to make precise v-toothed gears. Yet here was a device that clearly had them. Moreover, no one had any idea what the mechanism did.

Since 1902, then, people have been using ever-improving x-ray techniques and scanning methodologies to examine the device. For years, all they've learned is that it's even more complex than originally thought. Writing was found on some of the parts which hinted at possible explanations. More gears were discovered. Finally, enough information was available to take a shot at building one.

Michael Wright was one of those who took the shot, demonstrating that with sufficient time, patience, and skill, the gears could be manufactured with the precision seen in the actual device. When he was done, he was sure he knew what it was: A planetarium.

According to Mr. Wright, the Antikytherum could show the positions of the five known planets, but that wasn't a sure thing, because not all the gears in the original mechanism were available. He had to make assumptions about connecting gears. Now a new analysis has come up with another view.

An Anglo-Greek team, using the latest scanning techniques, has reported that the Antikythera Mechanism was an eclipse calculator. But even they are hedging their bets, because there is writing on the device that says “Mercury” and “Venus”, so at least two planets were being followed, perhaps to study their retrograde motion. The presence of these two planets gives Mr. Wright hope that his interpretation may still be part of the device's use.

So, in 150 BC, we have an analog computer being made to calculate eclipses and possibly planetary positions, a mere 2000 years before any such tool was available to the modern world. Not bad for a bunch of philosophers.

But, if you want to go back, say 5000 years, you'll find something that is almost as amazing as the Antikytherum. Michael Barsoum of Drexel University, and a native of Egypt, has shown that the great pyramids at Giza still have surprises to spring on us. It seems that the ancient Egyptians were not only great engineers and planners, they were pretty fair materials engineers and chemists. It seems that some of the key elements of the pyramids were concrete blocks, not solid limestone. Particularly, the inner and outer casing and the upper blocks were cast in place using a limestone concrete.

That will dent some cherished beliefs of those who have theorized about the construction of these monuments. If the Egyptians were able to cast blocks in place, then some of the problems concerning the ramps needed to haul blocks up to the top of the structures would no longer be so troubling.

There's plenty of evidence to suggest the presence of ramps used in building the pyramids, but how the highest points of the pyramids were reached was always unclear. Did they have one immensely long ramp, or did they wind the ramp around the outside of the structures? Or did they use some sort of combination? Now it seems, according to Mr. Barsoum's peer-reviewed paper, that they found a better way.

Not only does this idea deal eliminate the need to transport large block to very high places, it also explains how the apparent precision of construction could be maintained. With the ability to cast blocks, cumulative imperfections could be overcome by pouring “corrective” blocks as needed or by using the cement to level areas as required.

But here's the really good part. The cement used by the Egyptians has lasted 5000 years. Modern Portland cement, the most commonly used variety today, has a life of 150 years. Now Portland has its own advantages, I'm sure, probably in strenght. But there are many applications where the cement of the pyramids would work as well. If a modern counterpart of the Egyptian compound was used today, it would reduce cement-related pollution (Portland cement releases carbon dioxide) by 90% and wildly outlast the current materials. Not bad for a bunch of ancient tomb-builders.

We have so much to learn.

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