Semimajor axis (a), apocenter distance a(1 + e), and pericenter distance a(1 − e) vs. time of Jupiter (pink), Saturn (dark purple), Uranus (blue), and Neptune (light purple) along with the time and location of collisions with test particles for Uranus (blue triangles) and Neptune (purple stars) during the chaotic period. In this scenario (No Swap 1), the ice giants did not end with swapped positions: Neptune began and ended exterior to Uranus. Neptune was responsible for ∼80% of the total test particle collisions.