81P/Wild 2 backward in time orbital evolution during 1 Myr. Left panel: fraction of surviving clones (%) versus time from now (Myr). The colors represent the regions visited by the test particles (red: Jupiter family region; cyan: Centaur; blue: Transneptunian; yellow: Halley type). The resolution is 2 × 10⁴ yr. Right bottom panel: the % of surviving clones versus time from now (Myr), where N = 100 is the number of the initial test massless particles.