Introducing Chaos: A Graphic Guide (Graphic Guides)

by Iwona Abrams

Lorenz’s discovery of the phenomena of chaos is often related in an interesting story. One day in 1961, the story goes, Lorenz decided to take a short cut with his weather machine. He wanted to examine one sequence at greater length. So instead of starting the whole computer run from the beginning, he started half-way through. He tapped in the numbers straight from an earlier printout and went away to get a coffee. When he came back he could hardly believe his eyes. The newly generated weather was nowhere near the original. They were two completely different systems! Then he realized what had happened. He had tapped in the number .506, the number stored on the printout, whereas the original number from the computer’s memory was .506127. The small difference – one part in five thousand – was not inconsequential. Lorenz realized that minute differences in the initial conditions – like a puff of wind – could prove catastrophic.