WASHINGTON Edward Lorenz, the father of chaos theory, who showed how small actions could lead to major changes in what became known as the "butterfly effect," died of cancer on Wednesday at the age of 90, the Massachusetts Institute of Technology said.
Lorenz, a meteorologist, figured out in the 1960s that small differences in a dynamic system such as the atmosphere could set off enormous changes. In 1972 he presented a study entitled "Predictability: Does the Flap of a Butterfly's Wings in Brazil Set Off a Tornado in Texas?"
Born in 1917 in West Hartford, Connecticut, Lorenz earned degrees in mathematics from Dartmouth College in 1938, from Harvard University in 1940, and degrees in meteorology from MIT in 1943 and 1948.
While serving as a weather forecaster for the U.S. Army Air Corps in World War Two, he decided to study meteorology.
"As a boy I was always interested in doing things with numbers, and was also fascinated by changes in the weather," Lorenz wrote in an autobiography.
"By showing that certain deterministic systems have formal predictability limits, Lorenz put the last nail in the coffin of the Cartesian universe and fomented what some have called the third scientific revolution of the 20th century, following on the heels of relativity and quantum physics," said Kerry Emanuel, professor of atmospheric science at MIT.
"He was also a perfect gentleman, and through his intelligence, integrity and humility set a very high standard for his and succeeding generations," Emanuel added in a statement.
In 1991, Lorenz won the Kyoto Prize for basic sciences in the field of earth and planetary sciences.
The prize committee said Lorenz "made his boldest scientific achievement in discovering 'deterministic chaos,' a principle which has profoundly influenced a wide range of basic sciences and brought about one of the most dramatic changes in mankind's view of nature since Sir Isaac Newton."
Lorenz, who enjoyed hiking and cross-country skiing, stayed active until two weeks before his death at home in Cambridge, Massachusetts, his family said. He is survived by three children and four grandchildren.