About the rare huge-moon part - there’s been a recent discovery of a pair of young, still-forming exoplanets sharing the same orbit in a young star system - “PDS 70”; one protoplanet is in the L4 or L5 “Trojan” LaGrange point of the bigger one. Physicists reckon Theia may well have formed in one of Earth’s Trojan points, before being perturbed out onto a collision course by a third planet (thanks Jupiter)
So. While the planetary-collision-forming-a-huge-moon idea sure sounds wild, it might not be incredibly rare. Maybe.
We’re still at the very early stage of knowing what is normal for solar systems.
About the rare huge-moon part - there’s been a recent discovery of a pair of young, still-forming exoplanets sharing the same orbit in a young star system - “PDS 70”; one protoplanet is in the L4 or L5 “Trojan” LaGrange point of the bigger one. Physicists reckon Theia may well have formed in one of Earth’s Trojan points, before being perturbed out onto a collision course by a third planet (thanks Jupiter)
So. While the planetary-collision-forming-a-huge-moon idea sure sounds wild, it might not be incredibly rare. Maybe.
We’re still at the very early stage of knowing what is normal for solar systems.