Chaos - James Gleick [150]
The fundamental equations of general relativity are nonlinear—already a signal, we know by now, that chaos lurks. “People aren’t always well versed in its methods,” says Janna Levin, an astrophysicist and cosmologist at Barnard College of Columbia University. “Theoretical physics in particular is built on the notion of fundamental symmetries,” she notes. “For that reason, I think it’s been a difficult paradigm shift for theoretical physics to embrace.” Symmetries and symmetry groups tend to produce solvable equations—that’s why they work so well. When they work.
As a relativist, Levin deals in the biggest questions there are. (Is the universe infinite, for example, or just really big? Her work suggests big, or—if we want to be technical—topologically compact and multiconnected.) In studying the origin of the universe, Levin found herself dealing with chaos willy-nilly and ran into resistance. “When I first brought this work out, there was an insanely violent reaction against it,” she says. People thought chaos was fine “for complicated, grungy physical systems—not the pure, uncomplicated and virtual terrain of fundamental physics.”
We were working on chaos in pure general relativity without any grunge, and this was a tiny, tiny, little industry—working out chaos in a generic big bang, or collapse to a black hole, or in orbits around a black hole. People don’t think it’s a spooky word, but they’re surprised to see chaos play a role in something as ungrungy—no atoms or junk—as a purely relativistic system.
Astronomers had already found the fingerprints of chaos in violence on the sun’s surface, gaps in the asteroid belt, and the distribution of galaxies. Levin and her colleagues have found them in the exit from the big bang and in black holes. They predict that light trapped by a black hole can enter unstable chaotic orbits and be reemitted—making the black hole visible, if only briefly. Yes, chaos can light up black holes. “There are rational numbers to mine, fractal sets, and all kinds of truly beautiful consequences,” she says. “So on the one hand, people are horrified, on the other they’re mesmerized.” She does chaos in curved space-time. Einstein would be proud.
AS FOR ME, I never returned to chaos, but readers might spot seeds of all my later books in this one. I knew hardly anything about Richard Feynman, but he has a cameo here (see here). Isaac Newton has more than a cameo: he seems to be the antihero of chaos, or the god to be overthrown. I discovered only later, reading his notebooks and letters, how wrong I’d been about him. And for twenty years I’ve been pursuing a thread that began with something Rob Shaw told me, about chaos and information theory, as invented by Claude Shannon. Chaos is a creator of information—another apparent paradox. This thread connects with something Bernardo Hubemian said: that he was seeing complex behaviors emerge unexpectedly in information networks. Something was dawning, and we’re finally starting to see what it is.
James Gleick
Key West
February 2008
Notes on Sources
and Further Reading
THIS BOOK DRAWS on the words of about two hundred scientists, in public lectures, in technical writing, and most of all in interviews conducted from April 1984 to December 1986. Some of the scientists were specialists in chaos; others were not. Some made themselves available for many hours over a period of months, offering insights into the history and practice of science that are impossible to credit fully. A few provided unpublished written recollections.
Few useful secondary sources of information on chaos exist, and the lay reader in search of further reading will find few places to turn. Perhaps the first general introduction to chaos—still eloquently conveying the flavor of the subject and outlining some of the fundamental mathematics—was Douglas R. Hofstadter’s November 1981 column in Scientific American, reprinted in Metamagical Themas (New York: Basic Books, 1985). Two useful collections of the most influential