Patricia Sullivan in the Washington Post:
Edward N. Lorenz, 90, a meteorologist who laid the groundwork for chaos theory, memorably asking whether the flap of a butterfly’s wings in Brazil can set off a tornado in Texas, died of cancer April 16 at his home in Cambridge, Mass. He was an emeritus professor at the Massachusetts Institute of Technology.
At MIT, Dr. Lorenz accidentally discovered how small differences in the early stages of a dynamic system, such as the weather, can trigger such huge changes in later stages that the result is unpredictable and essentially random.
At the time, Dr. Lorenz was studying why it’s so hard to accurately forecast the weather, but the implications of his work go far beyond meteorology.
The new science of chaos fundamentally changed the way researchers address topics from the geometry of snowflakes to the predictability of which movies will become blockbusters. The butterfly effect became a popular way of describing unpredictability, most recently in “An Inconvenient Truth” (2006), the Academy Award-winning documentary with former Vice President Al Gore.
It also “brought about one of the most dramatic changes in mankind’s view of nature since Sir Isaac Newton,” said the committee that awarded Dr. Lorenz the 1991 Kyoto Prize for basic sciences.