Edward Lorenz was a meteorologist who discovered the butterfly effect in the 1960s. While working at MIT, he created a simplified computer model of weather patterns. One day, he restarted the model from a midway printout instead of from the beginning, and noticed the results diverged significantly. This led him to realize small changes in initial conditions could dramatically affect the long-term outcome, hence the metaphor of a butterfly's wings causing a hurricane. Lorenz's discovery helped establish the field of chaos theory and showed weather is inherently unpredictable in the long run due to its chaotic nature.