NEW YORK: Edward Lorenz, a meteorologist who became the father of the modern field of chaos theory, died on Wednesday of cancer in Massachusetts aged 90.

A professor at the Massachusetts Institute of Technology (MIT), Lorenz was the first to recognise what is now referred to as chaotic behaviour in the mathematical modelling of weather systems.

He found that small differences in a dynamic system, like the weather, “could trigger vast and often unsuspected results”, an MIT statement said. His studies led him to develop what became known as the “butterfly effect.” The term stemmed from his 1972 academic paper, “Predictability: does the flap of a butterfly’s wings in Brazil set off a tornado in Texas?”

The MIT said Lorenz’s early work “marked the beginning of a new field of study that impacted not just the field of mathematics but virtually every branch of science -- biological, physical and social”.

“Some scientists have since asserted that the 20th century will be remembered for three scientific revolutions -- relativity, quantum mechanics and chaos,” the statement said. Lorenz was working as a weather forecaster for the US Army Air Corps during World War II when he decided to pursue further study in meteorology.—AFP