Jupiter and Saturn were initialized in 3:2 mean-motion resonance, with libration angles φ _J = 3λ _S − 2λ _J − ϖ _J and φ _S = 3λ _S − 2λ _J − ϖ _S , where λ refers to the mean longitude and ϖ is the longitude of pericenter. The angle φ _J librates around 0 while φ _S librates around π. Only the first 1 × 10⁵ yr are shown for clarity. The ability of the resonance to survive 10⁸ yr was used to determine the set of initial conditions used in this simulation (Table 1), which we employ for all subsequent simulations in this work. The relatively weak and noisy resonant behavior evident here results from inclusion of all four giant planets as well as the low initial eccentricities of Jupiter and Saturn.