In 1961, MIT meteorologist Edward Lorenz was running weather calculations on an old computer. When he repeated a calculation, he got very different results, even though he thought he had used the same data. He later discovered that he had entered the numbers with different precision: six decimal places the first time and three the second time. This small difference produced a completely different result. Lorenz showed that chaotic systems can be extremely sensitive to their starting conditions. A very small change at the beginning can lead to a very different outcome later. This idea became known as the butterfly effect. After this discovery, Lorenz became increasingly interested in mathematics and shifted much of his research from meteorology to mathematics.