No. 139: Jan-Feb 2002
If only gravity and Newton's Laws ruled celestial motion, there would be no general solution to the hoary "three-body problem. But in the three special configurations illustrated, three bodies of equal mass can be shown to be stable. The third, the figure-of-eight, was not discovered until 1993 by C. Moore. Although mathematicians can prove it is stable, R. Montgomery admits:
There is no understanding of why the orbit is stable, from either a physical or mathematical point of view.
Certainly no figure-eight orbits have ever been observed in the cosmos so far, but who knows?.
The situation becomes really bizarre when more than three equal masses are considered. A few of the many stable, but manifestly weird, configurations are also illustrated here. These are among the simplest. To illustrate, C. Simo has found a stable choreography for 799 bodies cavorting happily and stably together in space. And he was using only his laptop!
(Appell, David; "Celestial Swingers," New Scientist, p. 36, August 4, 2001.)
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