The Butterfly Effect Michael Sidiropoulos, MEng The Butterfly Effect is commonly known as the thoroughly entertaining idea that a butterfly flapping its wings somewhere in the Amazon valley could cause a tornado in Texas. The idea goes back half a century ago when an MIT meteorology professor named Edward Lorenz made an amazing discovery. Lorenz was simulating weather patterns on his computer and before taking a coffee break, he rounded off one of his 12 variables from 0.506127 to 0.506. When he returned, he found that the entire trajectory of the simulation had changed dramatically. This unexpected result turned out to be Lorenz’s eureka moment. Such small changes in input are not supposed to have large consequences. The rounded variable was the atmospheric temperature, which was never measured beyond three decimal points. Lorenz experimented with the simulations and came to the idea that certain systems had a sensitive dependence on initial conditions. His conclusion was quite profound: because of the sensitivity of these systems, outcomes are unpredictable and forecasting the future can be nearly