Meterologist Edward N(orton) Lorenz died of cancer 16 April 2008. Born in 23 May 1917 in West Hartford, Connecticut, he is the developer of deterministic chaos, or chaos theory.
Chaos theory is succinctly stated as sensitive dependence on initial conditions. Sometimes known as the butterfly effect, it is exemplified by the possibility that a small perturbation, such as the flapping of a butterfly’s wings, can induce huge unforeseen consequences.
James Gleick’s 1988 book Chaos popularized the concept. In it, he told of Lorenz’s accidental discovery of the field in 1961. Lorenz was running simulations of weather using a simple computer model. One day, he wanted to repeat one of the simulations for a longer time, but instead of repeating the whole simulation, he started the second run in the middle, typing in numbers from the first run for the initial conditions. Though the program was the same, the two weather trajectories quickly diverged on completely separate paths. He first thought the computer was malfunctioning, but then realized that he had not entered the initial conditions exactly (the computer calculated to six decimal places, but the printout Lorenz copied from showed only three). Lorenz’s rounded-off numbers, which presented a difference of less than 0.1 percent, completely changed the end result. Even though his was a simplified model, Lorenz realized his discovery meant that perfect weather prediction was a fantasy. He published his findings in 1963.
His presentation at the meeting 1972 meeting of the American Association for the Advancement of Science was titled “Predictability: Does the Flap of a Butterfly’s Wings in Brazil Set Off a Tornado in Texas?”
Lorenz’s work actually postdated another chaos discoverer by nearly a century. French mathematician Henri Poincaré, in the late 1800s, realized the impossibility of solving the three-body problem (determining the gravitational interactions of three heavenly bodies), but his work was only connected to chaos theory relatively recently.
Lorenz received a bachelor’s in mathematics from Dartmouth College in 1938 and a master’s in math from Harvard in 1940. After working as a weather forecaster for the US Army Air Corps during World War II, he earned a master’s and a doctorate in meteorology from MIT in 1943 and 1948. He taught at MIT from 1948 until becoming an emeritus professor in 1987.
He is survived by two daughters (Cheryl and Nancy), a son (Edward), and four grandchildren. His wife, Jane Logan, died in 2001.