  The tumultuous early era of outer solar system evolution culminated when
Neptune migrated across the primordial Kuiper belt (PKB) and triggered a
dynamical instability among the giant planets. This event led to the ejection
of approximately 99.9\% of the PKB (here called the destabilized population),
heavy bombardment of the giant planet satellites, and the capture of Jupiter's
Trojans. While this scenario has been widely tested using dynamical models,
there have been fewer investigations into how the PKB, its destabilized
population, and the Trojans experienced collisional evolution. Here we examined
this issue for all three populations with the code Boulder. Our constraints
included the size-frequency distributions (SFDs) of the Trojan asteroids and
craters on the giant planet satellites. Using this combination, we solved for
the unknown disruption law affecting bodies in these populations. The weakest
ones, from an impact energy per mass perspective, were 20 m in diameter.
Overall, collisional evolution produces a power-law-like shape for
multikilometer Trojans and a wavy-shaped SFD in the PKB and destabilized
populations. The latter can explain (i) the shapes of the ancient and younger
crater SFDs observed on the giant planet satellites, (ii) the shapes of the
Jupiter family and long-period comet SFDs, which experienced different degrees
of collision evolution, and (iii) the present-day impact frequency of
superbolides on Jupiter and smaller projectiles on Saturn's rings. Our model
results also indicate that many observed comets, most which are smaller than 10
km in diameter, are likely to be gravitational aggregates formed by large-scale
collision events.
