On April 16, the world lost yet another remarkable scientific figure that marked the 20th century with his ideas of the chaos theory and the butterfly effect. Edward Norton Lorenz, who revolutionized meteorology by studying the effects of small variations in the initial condition of a dynamical system, which can lead to large and unpredictable variations in later stages of the system, died of cancer at the age of 90 on Wednesday, at his home in Cambridge, Massachusetts.

An emeritus professor at the Massachusetts Institute of Technology, Dr. Lorenz was both a mathematician and a meteorologist, who combined the two sciences in an attempt to accurately predict weather. Instead, he accidentally discovered the butterfly effect, which he presented in a study published in 1972 entitled “Predictability: Does the Flap of a Butterfly’s Wings in Brazil Set Off a Tornado in Texas?”

His chaos theory was only taken into consideration years after Lorenz wrote a paper on it. While trying to use a numerical computer model to obtain a weather prediction, and after accidentally typing less numeric characters than he should have, Lorenz discovered that the evolution of a dynamical system depends on the variables in the initial conditions.

“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, as quoted by Reuters.

In 1991, Lorenz was awarded the Kyoto Prize for basic sciences, in the field of earth and planetary sciences. Despite his age, he tried to stay active and was out hiking, and even continued his scientific work until recently, his daughter Cheryl Lorenz told the press.