Edward Norton Lorenz (born May 23, 1917), a research meteorologist at MIT, observed that minute variations in the initial values of variables in his primitive computer weather model (c. 1960) would result in grossly divergent weather patterns. This sensitive dependence on initial conditions came to be known as the Butterfly effect.

He went on to explore the underlying mathematics and published his conclusions in a seminal work in the annals of chaos theory, Deterministic Nonperiodic Flow, in which he described a relatively simple system of equations that resulted in a pattern of infinite complexity, the Lorenz attractor.

On 12 May 2004 Lorenz received the Dutch Buys Ballot medal .