  We demonstrate that the system of Jovian planets
(Sun+Jupiter+Saturn+Uranus+Neptune), integrated for 200 million years as an
isolated 5-body system using many sets of initial conditions all within the
uncertainty bounds of their currently known positions, can display both chaos
and near-integrability. The conclusion is consistent across four different
integrators, including several comparisons against integrations utilizing
quadruple precision. We demonstrate that the Wisdom-Holman symplectic map using
simple symplectic correctors as implemented in Mercury 6.2 (Chambers 1999)
gives a reliable characterization of the existence of chaos for a particular
initial condition only with timesteps less than about 10 days, corresponding to
about 400 steps per orbit. We also integrate the canonical DE405 initial
condition out to 5 Gy, and show that it has a Lyapunov Time of 200--400 My,
opening the remote possibility of accurate prediction of the Jovian planetary
positions for 5 Gy.
