More complicated models and new results follow, with a theory of gravitational encounters
developed in some detail, loss-cone dynamics, collisional evolution of nuclei with perturbational and mass-driven expansion.
On the other hand, it is likely that some planets are ejected from their early, turbulent solar systems, due to close gravitational encounters
with other planets or stars.
The misalignments attest to rough-and-tumble histories and may suggest that life flourished on Earth because the solar system avoided the brunt of close gravitational encounters
The only way theorists can account for these wayward trajectories is by assuming that direct collisions combined with close gravitational encounters