When the Butterfly Effect Took Flight
Half a century ago, Edward Lorenz, SM ’43, ScD ’48, overthrew the idea of the clockwork universe with his ground-breaking research on chaos. Now MIT professors are working to establish a climate research center in his name.
by Peter Dizikes February 22, 2011
On a winter day 50 years ago, Edward Lorenz, SM ’43, ScD ’48, a mild-mannered meteorology professor at MIT, entered some numbers into a computer program simulating weather patterns and then left his office to get a cup of coffee while the machine ran. When he returned, he noticed a result that would change the course of science.
The computer model was based on 12 variables, representing things like temperature and wind speed, whose values could be depicted on graphs as lines rising and falling over time. On this day, Lorenz was repeating a simulation he’d run earlier—but he had rounded off one variable from .506127 to .506. To his surprise, that tiny alteration drastically transformed the whole pattern his program produced, over two months of simulated weather.
The unexpected result led Lorenz to a powerful insight about the way nature works: small changes can have large consequences. The idea came to be known as the "butterfly effect" after Lorenz suggested that the flap of a butterfly’s wings might ultimately cause a tornado. And the butterfly effect, also known as "sensitive dependence on initial conditions," has a profound corollary: forecasting the future can be nearly impossible.
Like the results of a wing’s flutter, the influence of Lorenz’s work was nearly imperceptible at first but would resonate widely. In 1963, Lorenz condensed his findings into a paper, "Deterministic Nonperiodic Flow," which was cited exactly three times by researchers outside meteorology in the next decade. Yet his insight turned into the founding principle of chaos theory, which expanded rapidly during the 1970s and 1980s into fields as diverse as meteorology, geology, and biology. "It became a wonderful instance of a seemingly esoteric piece of mathematics that had experimentally verifiable applications in the real world," says Daniel Rothman, a professor of geophysics at MIT.
As many researchers would recognize by the 1980s, Lorenz’s work also challenged the classical understanding of nature. The laws that Isaac Newton published in 1687 had suggested a tidily predictable mechanical system—the "clockwork universe." Similarly, the French mathematician Pierre-Simon Laplace asserted in his 1814 volume A Philosophical Essay on Probabilities that if we knew everything about the universe in its current state, then "nothing would be uncertain and the future, as the past, would be present to [our] eyes."
Unpredictability plays no role in the universe of Newton and Laplace; in a deterministic sequence, as Lorenz once wrote, "only one thing can happen next." All future events are determined by initial conditions. Yet Lorenz’s own deterministic equations demonstrated how easily the dream of perfect knowledge founders in reality. That the tiny change in his simulation mattered so much showed, by extension, that the imprecision inherent in any human measurement could become magnified into wildly incorrect forecasts.
"It was philosophically very shocking," says Steven Strogatz, a professor of applied mathematics at Cornell and author of Nonlinear Dynamics and Chaos. "Determinism was equated with predictability before Lorenz. After Lorenz, we came to see that determinism might give you short-term predictability, but in the long run, things could be unpredictable. That’s what we associate with the word ‘chaos.’ "
The throwing hierarchy sequence
Mental (Intent the big picture which are trying to do) —–> Nervous System (creation of electrical signals to control the muscles) —–> Physiology (physical preparedness and condition of the neuromuscular system) ——> Biomechanics (external movement patterns of the body) ——> Physics (momentum transfer and forces applied to the baseball).
The only aspect of throwing of the baseball that that is immune from any changes (butterflies) is the physics of the throwing process. As stated in a previous post the fundamental law that determines all baseball movement is simply F=MA.
But how and when how you apply F=MA to the baseball never happens exactly the same way.