## Michele Henon is an astronomer at the Nice Observatory in southern France. For many years, during the 1960's particularly, he studied the dynamics of stars moving within galaxies, using computers as a way to understand the stability of their motions. His work was very much in the spirit of Poincare's approach to the classisical three-body problem: What important geometric structures govern their behavior?## The main property of these systems is that the energy of their motion is constant, to very high approximation. As a consequence, their chaotic dynamics are not described by simple attractors, but by objects that are markedly more difficult to analyze and visualize, existing on energy "surfaces" in three and higher dimensions.## During the 1970's he discovered a very simple iterated mapping that show a chaotic attractor, now called Henon's attractor, that allowed him to make a direct connection between deterministic chaos and fractals. The Henon attractor is self-similar. If you zoom in on the attractor in its state space you find more and more layers, much like filo dough or a croissant. |

© The Exploratorium, 1996