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From YubaNet.com Op-Ed
Clean? Organized? As you might have guessed, these words were not taken from the emotionally wrenching commentaries that are coming out of Sichuan Province, China, from NPR's "All Things Considered" co-host Melissa Block. When the magnitude 7.9 earthquake struck midday on Monday, her pastoral conversation with church staff in central China was audibly interrupted by low rumbling and random clatter. She reported that "As we're standing here, birds are flying, the ground is undulating under my feet, the cross on the top of the church is waving wildly... and bricks are falling off of the roof." She and her colleague Robert Siegel then headed closer to the epicenter, where the damage was much greater, and the death toll is expected to be in the tens of thousands. Their mist-hear reports hardly describe scenes of a "clean" and "organized" natural phenomenon. So how could I possibly describe earthquakes in such a cold, heartless manner as I did in the opening? Well, for starters, I didn't. Those were the words of Per Bak, a Danish theoretical physicist who had a knack for getting people upset with his confrontational style of challenging accepted wisdom. In his must-read book "How Nature Works", he describes how various complex phenomena in nature, and in society as well, evolve into what he called a "self-organized critical state", from which sudden changes, or "catastrophes", obey very simple laws. The surprising property of these so-called "power laws" is that they do not depend on the size, nor the nature, of the catastrophe. For instance, compared to 5.2 magnitude quakes, such as the one in Southern Illinois that harmlessly rumbled all the way to Tennessee in April, the frequency of devastating tremors such as the recent one in China is much, much lower. If one were to closely study the sandpile forming in the bottom of an hourglass instead, you would find the same relative frequencies of little and big avalanches. The "critical state" is the seemingly normal sandpile or NPR interview just before catastrophe strikes. It was discovered with very simple game-like mathematical models of sandpiles or plate tectonics. These models involve elementary rules governing what can be thought of as neighboring squares on an imaginary board. They also include factors that model the forces that characterize the actual system - gravity for sandpiles, and tension for plate tectonics. What Per Bak and his colleagues discovered was that many different models somehow developed into a common pattern prior to the catastrophic event. The complexity of this recurring pattern is perplexingly far greater than the model that created it, and is said to be an example of "emergence". The concept of emergence is familiar to social scientists and ecologists, but it is at odds with the reductionist philosophy of engineers and scientists. Physicists learn about nature by splitting things. Jazz lovers expect that an ensemble's performance will be more enjoyable than the sum of its parts, but cars and computers are designed component by component. It is the uneventful reliability of a Lexus that brings joy to its owners. From time to time, however, paradigms shift. There haven't been any violent tremors in the scientific community recently, but I sense that things are starting to quiver a bit. While nobody gets hurt doing experiments with sandpiles, Per Bak managed to profoundly offend many of his fellow physicists. Suffice to say that he relocated more often than most. Unfortunately, he died in 2002 as a result of a blood disorder in his mid-fifties. That hasn't meant an end to the shaking and rattling of the foundations of theoretical physics, however. Another theoretical physicist, Stanford professor and Nobel laureate Robert Laughlin sent seismic waves through the scientific community in 2005 with his book "A Different Universe - Reinventing Physics from the Bottom Down". The title still doesn't make any sense to me, but it is the content that ruffled feathers among his fellow physicists. Laughlin is also known to be less than diplomatic in his collegial interactions, but having a Nobel Prize on top of tenure adds up to lots of job security. Partly because of his maverick style, "A Different Universe" is a very enjoyable book. And like Per Bak's book, analogies with familiar social phenomena will help the non-scientist appreciate Laughlin's main argument, which registers way up there on the Richter scale. In Laughlin's view, it isn't just critical states that are self-organized, or emergent, but all the laws of physics. A better mathematical understanding of emergent phenomena probably won't reverse the fortunes of the US auto industry, but if it could help predict the timing of earthquakes then it would be well worth a little bit of faculty tension. Preston MacDougall is a chemistry professor at Middle Tennessee State University. His "Chemical Eye" commentaries are featured in the Arts and Public Affairs portion of the Murfreesboro/Nashville NPR station WMOT (wmot.org). © Copyright YubaNet.com |
