The title of a paper by Edward N. Lorenz of MIT, published in Volume 20 of the Journal of Atmospheric Sciences (March 1963).
This paper is probably among the top 100 most important scientific papers of the twentieth century. In this paper, he introduces the world to what will be later called chaos theory.
Lorenz describes how finite systems of deterministic ordinary differential equations give rise to strange and beautiful nonperiodic results. His discoveries drew into question the feasibility of very-long-range weather prediction, and opened new fields of mathematics.
Lorenz's butterfly came to be known as the Lorenz Attractor, which can be simply expressed using matrix form:
_
dy ( -8/3 0 y2 ) _ _
---- = ( 0 -10 10 ) * y ; y = ( y1 y2 y3 )
dt ( -y2 28 -1 )
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