Archives and past articles from the Philadelphia Inquirer, Philadelphia The beating of his wings pdf News, and Philly. 5 9 0 14 6. The home of over 5.
Easily clip, save and share what you find with family and friends. Easily download and save what you find. A very small change in initial conditions had created a significantly different outcome. The butterfly effect can also be demonstrated by very simple systems. He later proposed that such phenomena could be common, for example, in meteorology. In 1961, Lorenz was running a numerical computer model to redo a weather prediction from the middle of the previous run as a shortcut.
He entered the initial condition 0. 506 from the printout instead of entering the full precision 0. The result was a completely different weather scenario. At one point I decided to repeat some of the computations in order to examine what was happening in greater detail. I stopped the computer, typed in a line of numbers that it had printed out a while earlier, and set it running again. I went down the hall for a cup of coffee and returned after about an hour, during which time the computer had simulated about two months of weather.
The numbers being printed were nothing like the old ones. I immediately suspected a weak vacuum tube or some other computer trouble, which was not uncommon, but before calling for service I decided to see just where the mistake had occurred, knowing that this could speed up the servicing process. Instead of a sudden break, I found that the new values at first repeated the old ones, but soon afterward differed by one and then several units in the last decimal place, and then began to differ in the next to the last place and then in the place before that. In fact, the differences more or less steadily doubled in size every four days or so, until all resemblance with the original output disappeared somewhere in the second month.