The physical basis of chaos in the solar system is now better understood: in
all cases investigated so far, chaotic orbits result from overlapping
resonances. Perhaps the clearest examples are found in the asteroid belt.
Overlapping resonances account for its Kirkwood gaps and were used to predict
and find evidence for very narrow gaps in the outer belt. Further afield, about
one new ``short-period'' comet is discovered each year. They are believed to
come from the ``Kuiper Belt'' (at 40 AU or more) via chaotic orbits produced by
mean-motion and secular resonances with Neptune. Finally, the planetary system
itself is not immune from chaos. In the inner solar system, overlapping secular
resonances have been identified as the possible source of chaos. For example,
Mercury, in 10^{12} years, may suffer a close encounter with Venus or plunge
into the Sun. In the outer solar system, three-body resonances have been
identified as a source of chaos, but on an even longer time scale of 10^9 times
the age of the solar system. On the human time scale, the planets do follow
their orbits in a stately procession, and we can predict their trajectories for
hundreds of thousands of years. That is because the mavericks, with shorter
instability times, have long since been ejected. The solar system is not
stable; it is just old!Comment: 65 pages, 27 figure
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